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two varieties of this frog (reckoned by some as distinct species), of which the one
with orange-coloured under-parts is to be found in streams or marshes in the
: lowlands, while the yellow-bellied form lives at considerable elevations in the
mountains. They are essentially aquatic frogs, only leaving the water for a short
time in the spring, when they may be seen hopping on the land on their long
hind-legs. In the water they generally take up their position at some distance
from the bank, sitting with their heads slightly raised above the surface, and dis-
appearing with lightning-like speed at the slightest noise, to seek safety in the
mud at the bottom. The tadpoles grow to an unusually large size, and are
especially characterised by the great development of the tail-fin.

The third European representative of the family is the so-called
midwife-frog (Alytes obstetricans), of which the typical form inhabits
France, Switzerland, Belgium, and Western Germany, while a variety occurs in
(Spain and Portugal;
Spain being also the
home of the second
member of the genus (A.
pisternasii). From the
fire-bellied frog these two
species are distinguished
by the distinct external
tympanic membrane to
tbe ear, the elliptical and
vertical pupil of the eye,
land the moderate ex-
pansion of the transverse
[processes of the sacral
[vertebra. The common
species has the skin of
ttlie upper -parts warty,
while that of the under
surface is granular; the

glands near the head are small or indistinct, but there are large ones on the limbs ;
and the males have no vocal sac. The colour of the upper-parts is olive-grey, with
darker dots and irregular spots. Essentially an aquatic species, this frog derives
its name from the circumstance that the male takes charge of the eggs during
their development. The breeding-season lasts for upwards of six months, namely,
From March to August, although the eggs are laid only from March till June.
These are deposited by the female in the form of long chains, which may be
upwards of a yard and a half in length. These chains are taken by the male, and
wound round his legs and thighs ; and when thus loaded he retires to some burrow
or convenient hollow near the bank, where, at least during the daytime, he remains
in concealment until the tadpoles are ready for hatching. He then enters the
water, and the tadpoles soon come forth, and swim away to take care of them-




MALE OF MIDWIFE-FROG WITH CHAINS OF EGGS (nat. size).



286 FROGS AND TOADS.

selves; the hatching of the tadpoles taking place from June till September.
After the cares of the nursing period are over, the male loses his voice, which is
not resumed till the following February, when it is continued till August. The
males are more numerous than the females, and during the breeding-season their
loud croaking is almost continuous. From September till the beginning of March
the habits of this sex are similar to those of other frogs. The lower Miocene
strata of the Continent have yielded remains of an extinct frog belonging to
the same genus ; while in the rocks of the upper part of the same division of the
Tertiary period there occurs a gigantic frog belonging to the same family, which
has been referred to an extinct genus, under the name of Latonia.

The other two families Amphicmathodontidce and Hem i />]</'</<-
OtHer Famines. ..,,-,.... , .

tidcv belonging to the present suborder are not or much importance,

and are represented only by a small number of genera and species from Central
and South America. They are, however, of some interest, from the circumstance
that both the upper and lower jaws are furnished with teeth, in which respect they
agree with the sharp-nosed frog among the members of the first suborder.

THE TONGUELESS FROGS.
Families XENOPODID^E and



The members of the order hitherto considered are furnished with a well-
developed tongue, but in the order Aglossa, this organ is totally wanting.
The vertebrae resemble those of the disc-tongued frogs in having their articular
cups at the hinder-ends, but ribs are wanting. The metacoracoids correspond in
structure to those of the suborder Arcifera, although the cartilages at their edgrs
do not overlap. The tadpoles of these remarkable frogs exhibit the peculiarity of
having a pair of breathing-pores, after the loss of the external gills, situated
symmetrically on each side of the body. Each family is represented by a single
genus, respectively confined to Tropical Africa and Tropical South America.

The spur-toed frogs (Xenopus). of which there are three species
Spur-Toed Frog.

from Tropical Africa, are characterised as a family by the presence

of teeth in the upper jaw ; while they are further distinguished by the circula
pupil of the eye, the absence of an external tympanic membrane to the ear, t In-
free front-toes, and the webbed hind-foot, in which each of the three inner-toes itfi
furnished with a sharp, spur-like nail The smooth spur-toed frog (X. IcevisM
which is the species here represented, has a wide geographical distribution, ranging
from Abyssinia to the Cape; and is characterised by its smooth skin, marked
round the body with more or less distinctly defined tube-like lines. In colour it is*
dark brown above, and whitish beneath ; some individuals being uniform, while i
others are spotted with brown on the under surface. The spur-toed frogs arc
exclusively aquatic, pursuing even their prey beneath the surface of the water, -
and capturing it with their fore-feet. The pairing-season takes place in August, :
and the large eggs are laid singly. The tadpoles, which at birth have alread}^ lost
their external gills, on the third day after leaving the eggs develop a pair of'|
barbels hanging down from the corners of the mouth.



TONGUELESS GROUP.



287



Surinam Water- The second family, distinguished by the absence of teeth in both
Toad. jaws, is represented solely by the Surinam water - toad (Pipa
americana), which has long enjoyed a worldwide reputation, on account of the
very singular manner in which the eggs are lodged during the period of their
development. Agreeing with the spur-toed frogs in its circular pupil, smooth
palate, and absence of a tympanic membrane to the ear, the Surinam toad has the
extremities of the free front -toes dilated into radiating appendages, while the




SMOOTH SPUR-TOED FROG AND ITS TADPOLE (nat. size).

fully-webbed hind-toes are devoid of nails. In form the head is triangular and
much depressed, with the eye minute, one or two short tentacles on the lip in front
of the eye, a large flap at each corner of the mouth, and sometimes a third at the
tip of the muzzle. The skin, which is covered with small tubercles, is olive-brown
or blackish on the upper-parts, while beneath it is lighter, being sometimes orna-
mented with white spots, and at others with a black stripe clown the middle line.

The Surinam toad is an inhabitant of the damp forests of the Guianas and
Brazil, and the females deposit their eggs after the usual manner in the water. At
this period the skin of the back of the female becomes extremely soft arid much



288



FROGS AND TOADS.



thickened and the eggs, as soon as laid, are taken by the males and embedded one
by one in this softened skin, which soon closes over, so as to enclose each in a
separate cell. In these cells the eggs undergo the full course of development, the
juvenile toads issuing forth from their confinement in a perfect condition, although
their dimensions are, of course, small, and no gills being developed at any stage.
Although there may be as many as one hundred and twenty cells in the back of a



r '\




FEMALE SURINAM WATER-TOAD, SHOWING YOUNG IN THEIR CELLS (i IHlt. size).

single individual, the more usual number is from sixty to seventy. The period
from the deposition of the eggs to the appearance of the young toads is eighty-two
days, and the young, when first bursting through the covering of their cells,
generally protrude the head or one limb. Soon after the birth of her offspring the
female changes the superficial layer of her skin by rubbing it off against stones or
plants; the place occupied by each cell being then indicated by a small pit.
Except during the breeding-season, the pipa appears to be completely aquatic.



CHAPTER II.



NEWTS, SALAMANDERS, AND CCECILIANS,-
Orders CAUDATA AND APODA.'




newts and salamanders are readily distinguished from the frogs and toads by
the retention of the tail throughout life. Hence they are collectively designated
the Tailed Amphibians. Although they have generally two pairs of limbs, in a few
nstances the hind pair is wanting ; and in all cases the bones of the limbs are of a
normal type, the radius and ulna in the front pair, and the tibia and fibula in the
lind ones remaining distinct from one another. In the skull the frontal bones are
lot united with the parietals, and the palatine bones are distinct from the jaw-
bones or maxillae. Generally more or less lizard-like in form, the Tailed Amphibians
and ergo a less marked metamorphosis than the tailless group, some even retaining

throughout life. As regards their geographical distribution, the salamanders
ind newts, of which there are rather more than one hundred and twenty existing
species, are mainly characteristic of the Northern Hemisphere, being represented

by a few scattered forms in the Southern Hemisphere, and quite unknown in
Africa south of the Sahara and in Australasia. The northern part of the Old World
s the home of the true newts, of which four species extend into Northern Africa ;
ind it likewise contains one of the fish-like salamanders and the olm. True

VOL. v. 19



29 o NEWTS AND SALAMANDERS.

newts are very abundant in the western portion of this region, but as we
proceed eastwards they become less numerous, and we notice an approximation to
American types of the order, although only two genera are common to the Old and
New Worlds. North America is especially rich in Tailed Batrachians, containing
more than half the representatives of the entire suborder, and having the two-
legged salamanders (SirenidcK) peculiar to it. Axolotls are here especially abundant,
and there are also peculiar genera belonging to the families of the fish-like and
gilled salamanders. The Oriental region possesses only two species, namely, a
peculiar genus (Tylotriton) of newts in Yunan and the Eastern Himalaya, and
an axolotl in Siam. Tropical America, on the other hand, has ten species;
among which may be specially noticed the newts of the genus Spelerpes,
which are also represented by one species from Central America and the West
Indies, and two others from the mountains of Colombia, Ecuador, and Northern
Peru. Geologically, the group is by no means an old one, its earliest known
representative (Hylceobatrachus) occurring in the Wealden strata of Belgium ; and
these animals do not appear to have become abundant until the Tertiary epoch.

Nearly all newts and salamanders appear to be inhabitants of water during at
least some period of their existence ; some frequenting muddy swamps, and others
deep lakes or subterranean waters, while a few are found in mountain-tarns at
elevations of several thousand feet above the sea. Without exception nocturnal in
their habits, spending the day in slumber either concealed in hiding-places on land,
or at the bottom of the water in their aquatic haunts, and venturing abroad only
at evening or after heavy rain, they are all difficult of observation, and consequently
much still remains to be learnt with regard to their mode of life. The terrestrial
species generally frequent soft, shady, damp spots, but occasionally narrow valleys
or forests where they conceal themselves under stones or fallen trunks of trees, or
in holes in the earth. During their permanent or temporary sojourn in the water,
the adults of those species unprovided with external gills are obliged to come
periodically to the surface in order to breathe ; and while in that element all are
less completely nocturnal than when on land. Such species as are inhabitants of
cold regions undergo a period of torpidity during the winter months; while in
tropical regions others become quiescent when their haunts are dried up. They
exhibit a wonderful tenacity of life ; and when dried up in mud, or frozen in ice,
will awaken at the first shower of rain, or when their icy bonds are dissolved by
the sun's rays. They have also the capacity of reproducing lost limbs, apparently
any number of times. Although on land the majority of species are slow ;unl
sluggish in their movements, some salamanders from the south and west of Europe,
belonging to the genera Salamandrina and Chioglossa, run with the celerity of !
lizards ; while others, again, climb sloping or perpendicular faces of rock, like
geckos. In the water all swim quickly, mainly by means of serpentine movements
of the tail , although the water-newts are perhaps the most expert swimmers. All
are carnivorous in their diet, feeding chiefly upon molluscs, worms, spiders, and
insects. Their breeding-habits are peculiar in that there is usually no union
between the two sexes ; the females seizing the packets of spermatozoa deposited
by the males, and conveying them to their own reproductive chambers. While
some species lay eggs, in other cases the eggs are hatched within the bodies of the



SALAMANDERS. 291

female parent, and the tadpoles born alive, sometimes in a highly advanced stage
of development. In the case of the common salamander, during the breeding-season
the male enters the water first, and is followed shortly afterwards by the female,
who gives birth to her tadpoles; but in the Alpine salamander, the young are
born on land. The water-newts, on the other hand, lay eggs which are attached
to the stems and leaves of aquatic plants. The majority of the terrestrial
forms pass the earlier stages of their existence in the water, not leaving this
element till their lungs have become fully developed. In the tadpole -stage all
the members of the order are remarkably alike ; and this resemblance forbids any
wide separation of species like the olm, in which the external gills are retained,
from the true newts and salamanders, in which these appendages are lost at an
early period.

Although some of the larger kinds prey upon small fish, none of the newts
and salamanders can be said to be harmful to man ; while the terrestrial forms are
defended against all foes, except fish, frogs, and snakes, by the poisonous secretion
exuded by the glands of their skins ; water-newts are, however, devoured by
aquatic birds and mammals. The reputed noxious characters of the common
salamander, and its alleged immunity to the effects of fire, are, of course, purely
fabulous. The existing members of the order are divided into four families.



THE SALAMANDER TRIBE.
Family SALAMANDRID^;.

Comprising the typical members of the order, this family is specially char-
jrised by the absence of gills in the adult condition, the presence of upper
/bones or maxillae, as well as of teeth in both the upper and lower jaws, and
:ewise by the development of distinct eyelids. The family, which includes by
the great majority of the order, is divided into four subfamilies ; the first of
lich is characterised by having the teeth on the palate of the skull arranged in
longitudinal series, diverging posteriorly, and inserted on the inner margin
two backwardly-prolonged processes of the palatine bones. The median
sphenoid bone on the base of the skull is devoid of teeth, and the bodies of
;phe vertebrae are convex in front and concave behind.

Typical The typical genus of the first subfamily (Salamandrince) is

Salamanders, represented by three species, ranging from Central and Southern
Europe to the Caucasus, Syria, and Algeria, of which the best known is the common
)tted salamander (Salamandra maculosa). As a genus, these salamanders are
iracterised by the large and suboval tongue being free on the sides, and to a
in nil! degree also behind ; by the palatine teeth forming two curved series ; by the
presence of four front and five hind-toes ; and likewise by the nearly cylindrical
Section of the tail. The spotted species, which varies in length from 7 to 9 inches,
my be recognised by the length of the tail being slightly less than that of the head
Lnd body, and still more readily by its brilliant black and yellow coloration. The
lead is depressed and nearly as broad as long ; while the stout body is likewise
miewhat depressed, without any crest along the middle of the back ; and the short



292



NEWTS AND SALAMANDERS.



toes are devoid of any connecting webs. The smooth and shining skin is covered
on the upper-parts with pores, from which exudes a viscid and acrid secretion,
having decidedly poisonous properties. The yellow markings on the head, back,
and tail are arranged in two longitudinal series, broken up into more or less
irregularly-shaped patches. The species is an inhabitant of Central and Southern
Europe, Algeria, and Syria: and is the one which from time immemorial has been
dreaded, not only on account of its undoubtedly poisonous properties, but likewise
owing to the extraordinary superstition that if thrown on a fire it would not be
consumed. Frequenting moist and shady spots, either in the mountains among \
rocks, or in valleys and forests, the salamander passes the daytime in a kind of
torpid condition, only issuing forth from its hiding-places among stones or roots of I
trees either during rainy weather or after nightfall; its skin being quickly dried
up if exposed to the direct rays of the sun. Its movements on land are slow and
sluggish, its gait being a crawl with a marked lateral movement ; but in water




SPOTTED SALAMANDER (liat. size).

the creature swims strongly, mainly by the aid of its tail. Although frequently
found in the neighbourhood of its fellows, this salamander can scarcely be tenm-d
a sociable creature ; and it is only during the breeding-season that the two , i
live in company, From the. slowness of its own movements, it is only slov
moving creatures such as snails, worms, and beetles that the salamander
capture for its food ; although it is stated to occasionally kill small vertebra
Generally a large quantity of food is consumed, after which there is a long
sometimes lasting for as much as a month. During the pairing-season, which
in April or May, both sexes betake themselves to the water, when the fern
collect the spawn deposited by the males. Although the young are usually
alive, it occasionally happens that eggs are laid by the female, from which t
young almost immediately make their escape. The number of tadpoles produced
at a birth is very large, as many as fifty eggs being frequently found within the
body of the female ; while an instance is on record where upwards of forty-eight
young were born within four-and-twenty hours. More generally, however, from




SALAMANDERS.



2 93



eight to sixteen, and less commonly from twenty-four to thirty tadpoles make
their appearance into the world during a period of from two to five days.
Generally all these are in an equally advanced state of development ; but sometimes
in captivity both eggs and tadpoles are produced simultaneously, the former being
translucent and showing the young tadpoles curled up within them. The tadpoles,
which are generally produced in clear, running water, are blackish grey in colour,
with a more or less well-marked greenish tinge ; but there are small golden spots
on the back, which gradually increase in size with advancing age. The skin
also gradually becomes less shining and smooth, while at the same time the gills
shrink, till about August or September the young salamanders quit the water
for a terrestrial life. A few may, however, remain till as late as October. It is
remarkable that the young salamander is rather inferior in size to the tadpole in




ALPINE SALAMANDER (nat. size).

the latest stage of development ; and it is not yet known for how ,long a period
[t continues to grow after leaving the water. In aquaria salamanders develop
[nore quickly, and have been known to leave the water within three weeks,
winter sleep generally takes place in moss-lined crannies, well protected from
[he frost, and may endure till the commencement of April.

Alpine The Alpine, or black salamander (S. atra), inhabiting the Alps

lamander. a fc elevations of from three to ten thousand feet, is a smaller animal
[han the last, from which it may be at once distinguished by its inferior dimen-
|ioiis. Ranging from the Alps into Styria, Carinthia, and some of the mountains
Wiirtemberg and Bavaria, this species inhabits moist woods or the banks of
lountain-streams, where it is generally found in small family-parties, which
[onceal themselves after the manner of their kind beneath stones and moss, or at
le roots of! the Alpine rose. Although resembling the spotted salamander in



2 9 4 NEWTS AND SALAMANDERS.

producing living young, this species differs in that never more than two are
born at a time. The most remarkable circumstance connected with the repro-
duction of the species is, however, that from thirty to forty eggs are found in the
oviducts of the females, out of which only one develops in each oviduct, at
the cost of the remainder, which form a glutinous mass surrounding the develop-
ing egg, and in which the liberated tadpole can afterwards freely move. There
are also some fifteen unimpregnated eggs in each oviduct, which serve as the food
of the newly-hatched tadpole. The tadpole, which does not attain its full size till
after birth, lies in the oviduct of the female with its tail curled, but is capable of
moving and even turning round. Its gills are of unusual length, being nearly
half as long as the whole body ; but before birth these shrivel up and are repre-
sented by mere knobs, so that the whole of the tadpole stage is passed through
within the maternal body. Tadpoles that have been taken from the oviduct
before completing their development will, however, live in water like those of the
other species ; thus proving that the species originally went through a temporary
aquatic existence. Although the two young salamanders are generally born at
the same time, occasionally one develops more rapidly than the other, so that
there may be an interval of several days between the births of the two. At the
pairing-seasons these salamanders enter the water for a few hours, but are other-
wise purely terrestrial. The third representative of the genus is the Caucasian
salamander (S. caucasica), distinguished from both the others by the tail being
longer than the head and body. In colour this species is black, with irregular
rows of round yellow spots down the back.

Spanish This species (Chioglossa lusitanica) is the sole representative

Salamander. o f a genus distinguished from the last by the tongue being supported
on a median protrusile pedicle, and consequently free everywhere except on the
front half of the median line. Considerably smaller than the spotted salamander,
this species is dark brown in colour, rather lighter above than below, with two
broad reddish golden bands along the body, separated from one another by a dark
line along the middle of the back. It inhabits the north-western districts of Spain
and the whole of Portugal.

The newts (genus Molge) form an extensive group, of aquatic
habits, spread over Europe, Northern Asia, and North America, and
are the only members of the order found within the limits of the British Islan
Having the same number of toes as the salamanders, they are distinguished
the highly compressed and rudder-like tail, as well as by the frequent presem
of a fin-like crest down the middle of the back, which often attains a speci
development in the males during the breeding-season. With the exception of t
crested newt, the skull differs from that of the salamanders by the presence of
ligamentous or bony arch connecting the frontal with the squamosal bone; and
the palatine teeth form two nearly straight or slightly curved series. The tongue
is free along the sides, but may be either attached or more or less free behind.
The genus may be divided into two main groups, according to the presence o
absence of a crest down the middle of the back of the males ; and each of '
(lifsu may be further subdivided according to the characters of the so-called'
frouto-squainosal arch.



NEWTS. 295

Belonging to the group in which the males are provided with
a dorsal crest, this species (M. cristata) differs from all the others in



Online LibraryRichard LydekkerThe new natural history (Volume 5) → online text (page 31 of 62)