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SAUROCEPHALID^, etc.

Before proceeding to the consideration of the herrings, we may briefly refer
to a group of more or less closely allied extinct families, mainly characteristic of
the Cretaceous period, but also represented in the lower Tertiaries. From the

large size of their
lanciform, reptile-
like teeth, all the
members of the group
are collectively
spoken of as the
saurodont fishes.

SKELETON OF A SAURODONT FISH (FAiryphoUs).

The first family

(Dercetidce) is typified by the genus Dercetis, of the Chalk, and is characterised by
the elongated form of the body, the large size of the teeth, which are implanted in
sockets, and the presence of several rows of large triangular bony plates along the
sides of the body ; the muzzle being frequently produced into a beak, and the dorsal
fin single. Nearly allied is the family (Enchodontidce) represented by the widely
spread Cretaceous genera Enchodus and Eurypholis ; these fishes having the body
moderately compressed, and either naked or partially protected by bony plates,
and the elongated upper jawbones armed (like those of the lower jaw) with small,
immovably welded teeth. To a third family belongs the genus Sauroc<'/>/i<i/ nx,
from the North American Cretaceous, which, together with the allied forms, has
the body much compressed, the large upper jaw armed with powerful teeth, usually
set in sockets, and a single series of similar teeth in the lower jaw, the palatine
bones being toothless. A peculiarity of the vertebrae of these fishes, with the
exception of those of the neck, is the presence of two deep grooves and pits on
their sides. Some of these fish attained huge dimensions: the American and
Australian Cretaceous genus Por1lt<>n* being distinguished by the presence of an
enormous bony crest in the middle line of the skull.




HERRING TRIBE. 487

THE HERRING TRIBE, Family CLUPEID^E.

Second to none in their commercial importance, the herring tribe are remark-
able for the enormous number of individuals by which several of the species
are represented rather than for the multiplicity of the species themselves; this
being probably one of the chief reasons for the great value of these fishes as a
food-supply. Although the existing representatives of the family may be readily
distinguished from the salmonoids by the absence of a fatty fin, yet extinct forms
indicate such an intimate connection between the two groups as to induce some
naturalists to include both in a single family. Whatever may be the ultimate
verdict on this point, in a work like the present, where we are mainly concerned
with living types, it is obviously preferable to follow the ordinary system. While
the typical representatives of the family have the parietal bones of the skull
separated by the supraoccipital and but one true tail-vertebra, in the genus Elops
the parietals are in contact, and there are two caudal vertebral On this account
it has been proposed to make the latter genus the type of a distinct family ; a
similar proposal having been made in the case of an analogous departure from the
ordinary type among the salmonoids. In addition to the absence of the fatty fin,
most herrings are characterised by the presence of small bony plates on the lower
margin of the body. Externally the whole body is scaled, with the lateral line
mostly wanting ; while the head is generally naked, and the muzzle always without
barbels. The under surface is more or less compressed, and generally so much
so as to form a sharp edge, which is usually serrated. In the gill-cover the four
elements are present, and the gill-openings are in most cases very wide. Both
premaxillas and maxillae enter into the formation of the margin of the upper jaw,
but each of the latter bones is peculiar in being composed of three separate pieces.
The single short dorsal fin has a small or moderate number of weak rays, and the
anal may be many-rayed. The stomach is furnished with a blind sac ; the air-
bladder is of more or less simple structure ; and well-developed false gills are usually
present. Distributed over all temperate and tropical seas, herrings are mainly
littoral fishes, none of them being inhabitants of deep water, and none truly
pelagic. Although the majority are marine, many of them will enter fresh water,
and some live permanently therein, while it is probable that all can be acclimatised
to such conditions. As might have been expected from their generalised structure,
herrings are an ancient group, the typical genus dating from the period of the
Chalk, while anchovies and other existing generic types are known from the
Eocene. A number of more less nearly allied Cretaceous genera appear to connect
the family very closely with the higher ganoids.

The common herring- (Clupea harengus) belongs to a group of
genera characterised by the equality in the length of the two jaws,
the presence of free fatty lids to the eyes, and the serration of the lower border of
the hinder part of the body ; the typical herrings being distinguished from the
allied genera by the anal fin being of moderate length, with less than thirty rays,
and the serration of the under surface commencing from the chest or point of
origin of the pectoral fins. Usually the scales are of moderate or large size,
although they may be small ; the cleft of the mouth is of medium width ; and if



TUBE-B LADDERED GROUP

teeth are present at all, they are rudimental and deciduous. In position the dorsal
fin is opposite the anal, and the caudal is deeply forked. Represented by some
sixty species, the genus has a distribution coextensive with that of the family ;
but whereas the flesh of the majority of its representatives is of excellent quality,
that of some tropical forms may acquire poisonous properties. In the case of such
a well-known fish as the common herring it will be superfluous to give any descrip-
tion; but it maybe mentioned that this species may be distinguished from its allies
by the presence of a patch of small ovate teeth on the vomer. It has also the
dorsal fin situated exactly midway between the extremity of the muzzle, and the
longest ray of the caudal fin, and the pelvic fins are directly under the dorsal.




SHAD, SPRATS, AND HERRING (the shad i, the others \ nat. size).

Whitebait are for the most part the young of this species. Common to both s
of the cooler regions of the Northern Atlantic, the herring ranges eastwards
the seas on the north of Asia. Associating in shoals numbering millions
individuals, the herring feeds upon crustaceans, worms, insects, and the young an<
eggs of other fishes, as well as those of its own kind. " During the day," wri
Mr. J. M. Mitchell, " the shoals are sometimes observable near the surface, and ma
be seen playing on the water, as the fishermen call it, making a ripple, a dar
roughness similar to what we may see at the beginning of a slight breeze, this bein
somewhat observable without the appearance of either whales or birds. The passi
near or over them of a boat or ship makes them instantly dart off in every din-
tion, leaving the appearance of long trails of light, if at night. We have be



HERRING TRIBE. 489

informed by fishermen of Newhaven that the herrings take considerable flights out
of the sea ; off Stonehaven, in the month of September, one of these men having
seen a shoal, after the spawning-season, rise up out of the water in a vast mass of
many yards in extent, sparkling and flashing and flying several feet above the
surface. . . On some of the coasts, as on those of Norway, the herring-shoals are
frequently accompanied or pursued by numbers of whales and aquatic birds, which
arc all occupied in preying on them. The large dark masses of the whales rising
and blowing and throwing up great quantities of the herring into the air, sparkling
and glittering in the clear winter day ; the constant movements of the birds, with
their shrill notes, actively engaged in seizing their easily-obtained food, vying with
man in their attacks on the countless myriads of herrings, form a most wonderful
sight. . . . When the herrings swim near the surface, if it is calm weather, the
sound of their motion is distinctly heard at a small distance ; and at night their

lotion, if rapid, causes a beautiful bright line from the phosphorescent quality of
the skin ; and it is also said, that when a great body of them swims near the surface,
their presence is ascertained by a strong fishy smell." In another passage, after
stating that the idea of fish migrating from the Arctic regions southwards is purely
erroneous, the same author observes that " from all circumstances known of the
uitural history of the herring, in regard to its visits on our own coasts and the

msts of other countries, it is reasonable to suppose that it inhabits the seas in the
leighbourhood of the coasts on which it spawns, and that it arrives at particular
seasons near the coasts for the purpose of spawning, the shoals leaving the coasts

immediately thereafter ; and the early or late, distant or near, approach to the

mst in different years, perhaps depends on the clear and warm, or dark and cold

reather of the seasons, as well as upon the depth of water at the feeding and
spawning-grounds." Herrings have been kept in a brackish-water pond com-

mnicating with the Humber, where they became dwarfed in size,

The much smaller sprat (C. sprattus), so abundant on the Atlantic coasts of

Europe, differs by the absence of vomerine teeth ; while the shad (C. finta\ shown
the upper figure of the illustration on p. 488, may be distinguished by having
me or more black blotches on the sides. In this species, which not only frequents
the European coasts, but ascends rivers, and is abundant in the Nile, the bony gill-
rakers, of which there are from twenty-one to twenty-seven on the horizontal
Dortion of the outer gill-arch, are short and stout. On the other hand, in the
similarly spotted allice-shad (C. alosa) the gill-rakers are very long and fine, and
number from sixty to eighty on the part mentioned. Both the shads are consider-
ably larger than the herring. Whereas in both the herring and the sprat the
opercular bone is smooth, in the pilchard or sardine (C. pilchardus) this part is
marked by ridges radiating towards the subopercular. This species is abundant
in the English Channel, the seas of Spain and Portugal, and the Mediterranean ;
Vigo Bay being noted for its sardine-fishery.

The following account of the sardine-fishery is taken from the Asian news-
paper. " Sardines are migratory in their habits, and the exact locale of their
Avinter quarters, despite frequent research on the point, remains a mystery. In
ordinary years it is the custom for the fish to make their first appearance
on the coast of Africa about the end of March, then passing northward in



49 o TUBE-BLADDERED GROUP.

large shoals, they follow the coast of Portugal, crossing the Bay of Biscay, till
they strike the coasts of Vendee in the month of April or May. Before day-
break the fishing-boats leave port to search for the shoals of sardines ; indeed,
many leave in the evening and anchor at sea. When a peculiar bubbling of
the water reveals the fish, the nets are immediately thrown. Each net is
from 900 to 1000 yards in length, about 3 yards in width, and black in colour.
On the upper part of the net are corkfloats, and on the lower part leaden
sinkers to keep the net in an upright position. The oarsmen, generally two in
number, row always either against the wind or the tide. One man casts the net
as the boat advances, while another throws the roque into the water. This bait is
an important feature of the sardine catch, as it is expensive, and fishermen often lose
considerable quantities of it. It is made of the roe of cod-fish or mackerel mixed
with clay, and costs from 30s. to 3, 10s. a barrel, and it is thrown into the water
in small balls, which slowly dissolve and sink. At nightfall the boats return to
port, where they sell their fish to the canners at prices varying according to the
abundance of the catch and the size and freshness of the fish. Sales are made by
the ' thousand,' but this term does not always indicate exactly a thousand sardines.
For example, at Belle Isle 1240 fish are supposed to make a thousand. Factories
for preserving sardines are located at all the ports, for the fish spoil easily and
cannot bear transportation. The fishermen convey the sardines to the factories in
baskets. The process of canning is as follows : The sardines are spread on boards
and salted, and the heads removed. They are then thrown into brine, where they
remain half an hour. They are next washed in clean water and dried on screens.
This work is done almost entirely by the wives and children of the fishermen,
their united wages during the season enabling the family to subsist during the
following winter. After the fish have been thoroughly dried they are cooked by
dipping them for a few minutes in oil heated to 212 F. They are again drained
and handed over to workmen, who pack them in small tin boxes, which are filled
with pure olive oil and then soldered. The oil used is imported from the province
of Bari, Italy. The boxes are next thrown into hot water, where they remain for
two or three hours, according to the size of the boxes. When withdrawn, the boxes
are first cooled, then rubbed with sawdust to cleanse and polish them, and packed
in wooden cases of one hundred boxes for export : during their immersion in the
boiling water oil will escape from all boxes not properly soldered, and in such cases
the loss is sustained by the solderer, but so skilful are those in the craft that a good
workman rarely misses more than two or three boxes per hundred Periodically
the fish entirely disappear for a season or so from the coasts of Spain, France, j
Italy."

Fresh-Water Especial interest attaches to the Australian fresh-water lid-rings

Herrings. (Di/plowiyetus), which differ from the typical genus in having a series
of bony plates similar to those on the lower surface between the back of the head
and the dorsal fin, since a similar type of fish has been long known in a fossil state,
having been obtained from the Cretaceous rocks of Brazil and Syria, and the Lower
Tertiary of the United States and Britain. The persistence at the j.ivsent day of
this ancient type of herring in the fresh waters of Australia is an instance
of the survival of primitive forms of life in that region.



SMOOTH-HEADS AND SOUTHERN SALMON.



491



Anchovies.



Elops.






The common anchovy of the Mediterranean (Engraulis encras-
sicholus) is the typical representative of a second widely-spread
genus, with over forty species, differing from the last by the more or less nearly
conical muzzle projecting beyond the lower jaw, and also by the eyes being covered
with skin ; while the cleft of the mouth is deep, and the tail-fin forked. In most
cases each side of the body is ornamented with a broad longitudinal silvery stripe.
The common anchovy is met with off the south-western coasts of England, but
wanders still further to the north, and serves to supply the markets of the world.
Some species have the rays of the pectoral fins produced, and thus lead on to the
allied Oriental genus Coilia, in which the foremost rays of these fins are fila-
mentous, and the exceedingly long anal fin extends backwards to join the caudal.

A very distinct group, which, as already mentioned, is regarded
by some as a distinct family, is typically represented by the two
species of the tropical and subtropical genus Elops. In addition to the characters
of the skull noticed in p. 487, these fish have the lower jaw longer, a thin plate of
bone -extending backwards from the point of union of the two branches of the
lower jaw, and the whole under surface of the body smooth and rounded. The
common species grows to a yard in length. An allied type (Rhacholepis) occurs
in the Cretaceous rocks of Brazil.

The earliest allies of the herring tribe seem to be the extinct
slender-scales (Leptolepididcv), of which there are a considerable
number of species, ranging throughout the Jurassic period. In the typical
Leptolepis the dorsal fin is placed immediately over the pelvic pair, but in the
nearly allied Thrissops it is over the anal. Although there are a number of other
extinct generic types, more or less closely related to the herrings, it is impossible
to enter into their consideration here, and we accordingly pass on to



Slender Scales.




BLACK SMOOTH-HEAD ($ lUlt. Size).



THE SMOOTH-HEADS AND SOUTHERN SALMON.
Families ALEPOOEPHALW.E and HAPLOCHITOKID^:.

The first of these two families is typically represented by the
genus Alepocephalux, of which a species (A. niger) is shown in the
annexed illustration. While agreeing with the typical salmonoids in the structure



Smooth-Heads.



492



TUBE-BLADDERED GROUP.



of the skull and the presence of two true tail-vertebrae, as well as in other features,
these fish may be distinguished by the absence of the fatty fin. Whereas barbels
are invariably absent, and the head is always naked, the body may be either scaled
or bare. Both premaxillee and maxillge enter into the formation of the margin of
the upper jaw, the former occupying the upper front edge of the latter. All the
elements of the gill-cover are present ; the dorsal fin is situated opposite the anal
in the caudal region ; the gill-openings are very wide ; false gills are present ; the
air-bladder is wanting ; and the curved stomach has no blind appendage. All
these fish have the teeth feebly developed, the eye large, and the bones thin ; while
they are remarkable for their uniformly black coloration. The whole of them are
deep-sea fishes, with an apparently almost cosmopolitan distribution, some of them
having been taken at a depth of over two thousand fathoms. Whereas the body
of the typical genus is covered with thin cycloid scales, in another type the place of
these is taken by fine granules.




ZEBRA-SALMON.



By this name may be designated two genera of fresh- water fish.
Southern Salmon. . . , ,

constituting a iamily which represents the salmonoids in the Southern

Hemisphere ; the zebra-salmon (Haplochiton zebra) being figured as an example of
the typical genus. Like the salmon and herrings, devoid of barbels, these fish
agree with the former in the presence of a fatty fin, but differ in having the margin
of the upper jaw formed solely by the premaxillary bones. The body may be
either naked or covered with scales; the gill-opening is wide; false gills are
present ; and the air-bladder is simple. The ovaries are in the form of plates, and,
in the absence of a duct, the eggs fall into the abdominal cavity. The species of
the typical genus, which, although devoid of scales, are externally very similar in
appearance to trout, are confined to the lakes and rivers of Chili and the extreme
south of Patagonia and the Falkland Islands. In South Australia and iSYw
Zealand the family is represented by the genus Prototroctes, in which the body is
scaled and the jaws are armed with minute teeth ; the New Zealand species being
commonly known to the colonists as the grayling.



SALMON TRIBE.



THE SALMON TRIBE, Family



493



With the salmon tribe, which include the finest and " gamest " of all fresh-water
fish, we come to the last group of the true bony fishes, which may be distinguished
from the preceding family by the margin of the upper jaw being formed by the pre-
maxillse in front and by the maxilla at the sides. As a rule, the body is scaled,
while the head is invariably naked ; the under surface of the body being rounded.




SALMON AND SEA-TROUT (J liat. size).

Inhabiting alike salt and fresh-waters, those species which spend a part or the
whole of their existence in rivers or lakes are in the main confined to the Temperate
and Arctic zones of the Northern Hemisphere, although one outlying genus occurs
in New Zealand; and whereas the majority of the marine forms are deep-sea
fishes, two genera are entirely pelagic in their habits. A considerable number of
the species inhabiting fresh waters descend periodically or occasionally to the sea ;
and in some cases it is perhaps rather difficult to say whether these fishes should
be regarded as marine or fresh-water. All the salmonoids are remarkable for the



494 TUBE-BLADDERED GROUP.

excellent quality of their flesh, which in many forms is of a more or less strongly
marked pinkish hue, brought about by the crustaceans on which these carnivorous
fishes so largely feed. Fossil marine salmonoids, some of which belong to existing
genera, are known from the upper Cretaceous period, several of them apparently
connecting the family very closely with the herrings. As mentioned above (p. 487)
the more typical members of the family have the parietal bones of the skull
separated from one another by the supraoccipital, but in Coreyonus and ThymallU^
they unite together in front of it. There is, however, a genus (Stenodux) in
which both conditions exist, so that there is no justification for making the
union of the parietals a reason for referring Coregonus to a family apart. In all
cases the supraoccipital extends forwards to join the frontals (passing beneath
the parietals in the genera where those unite), and is thus quite different from the
condition obtaining in the carps and characinoids.

Having the dorsal nearly or quite opposite the pelvic fins, the
members of the typical genus Salmo are characterised by the small
size of the scales of the body, the strong and fully developed teeth, and the presence
of not more than fourteen rays in the anal fin, and of numerous blind appendages
to the intestine. The cleft of the mouth is always deep, the maxilla extending up to
or beyond the line of the eye. Conical teeth are present not only in the margins
of the jaws, but likewise on the vomer and palatine bones, as well as on the tongue,
although there are none on the pterygoids. The eggs are remarkable for their
relatively large size ; and the young, like those of most or all the other genera, arc
marked with dark crossbars. In the males the lower jaw is more developed than in
the females, and at certain seasons may be developed into an upturned hook. The
genus is confined to the colder portions of the Northern Hemisphere, its southern
limits in the Old World being the rivers of the Hindu Kush and the Atlas rangi-,
and in America the rivers flowing into the head of the Gulf of California.

Few zoological subjects have given rise to a greater amount of discussion than
the life-history of the members of this genus, and the number of species by which
it is represented. As regards the latter point, great difference of opinion still
prevails among experts. Thus, for instance, Day considered that all the
indigenous British salmonoids might be arranged under three specific types,
namely, the salmon, the trout, and the charr; while other authorities admit an
almost endless amount of species. The subject is not one which admits of dis-
cussion in this work ; and we shall accordingly confine our notice to the salmon, the
typical sea- and river-t ( rout, and the charr. As regards the variability of these
fishes we may, however, quote a passage from Dr. Giinther, who writes that " these
are dependent on age, sex, and sexual development, food, and the properties of tin
water. Some of the species interbreed, and the hybrids mix again with one of the
parent species, thus producing an offspring more or less similar to the pure breec
The coloration is, first of all, subject to variation ; and consequently this charactei
but rarely assists in distinguishing a species, there being not one which would sho>
in all stages of development the same kind of coloration. The young of all the
species are barred ; and this is so constantly the case that it may be used as
generic, or even as a family character, not being peculiar to tf<(lmo alone, but als
common to ThymalllM, and probably to Coregonus. The number of bars is not




S A LAWN TRIBE. 495

quite constant, but the migratory trout have two (and even three) more than the
river-trout. In some waters river-trout remain small, and frequently retain the
parr-marks all their lifetime ; at certain seasons a new coat of scales overlays the
parr-marks, rendering them invisible for a time. When the salmonoids have
passed this ' parr ' state, the coloration becomes much more diversified. The males,
especially during and immediately after the spawning- time, are more intensely
coloured and variegated than the females ; specimens which have not attained to



Online LibraryRichard LydekkerThe new natural history (Volume 5) → online text (page 52 of 62)