The Cambridge natural history, Vol. 08 (of 10)Gadow, Hans
Science
The Cambridge natural history, Vol. 08 (of 10)
Gadow, Hans
Animals
Fischer-Sigwart[77] gives the following account of the growth of this
species. The male took to the water, with its load of twenty to thirty
eggs, on the 6th of June. The larvae escaped out at once, 16-17 mm. long,
the body measuring 5 mm. On the 14th they had reached 32 mm. in length,
whereupon they grew very slowly, although they were well fed, in a
temperature of about 50° F. This same brood did not metamorphose until May
of the next year. The growth took place as follows:–The hind-limbs appeared
on the 8th of September, when the tadpoles were 50 mm. long; by the middle
of the next May they {160}had reached their greatest length, 76 mm., the
hind-limbs being 18 mm. long, whilst the fore-legs were just indicated. On
the 21st of May the hind-limbs were 27 mm. long, and the whole creature was
practically metamorphosed, except for the tail. The latter was resorbed on
the 13th of July, and the little toads, 25 mm. in length, were actually
smaller, certainly far less bulky and heavy, than the tadpoles, which had
required one year and a quarter for their metamorphosis.
The early broods probably finish their development by the autumn of the
same year, but those which are born later, in July and August, certainly
hibernate in the water. I have found very small tadpoles, scarcely 15 mm.
long, on the Cantabrian mountains as late as the end of September, and
rather large ones in the spring at the time of first pairing; the fact that
this takes place during the whole summer explains the occurrence of
tadpoles in all stages of development almost the whole year round.
_A. cisternasi_ has only two palmar tubercles, the middle or third one of
_A. obstetricans_ being absent; the outer finger is short and thick.
Instead of a very long and wide fronto-parietal fontanelle, the
fronto-parietal bones diverge only in front so that there are two
fontanelles, a small one in the parietal and a large triangular one in the
frontal region. The limbs are relatively shorter and stouter in conformity
with the habits of this species, which prefers to burrow in sandy
localities. Otherwise it leads the same kind of life as _A. obstetricans_,
and the male carries the eggs. It has hitherto been found in Central Spain
and in the middle provinces of Portugal.
_Liopelma_ is intermediate between _Alytes_ and _Bombinator_, agreeing with
the latter, in conformity with its essentially aquatic life, in the absence
of a tympanum, while the Eustachian tubes are entirely suppressed. The
tongue is disc-shaped, but is slightly free behind. The pupil is
triangular. The male is devoid of a vocal sac. _L. hochstetteri_ is the
sole representative of the Amphibia in New Zealand, where it is apparently
rare. The upper parts are covered with smooth tubercles, and are dark brown
with blackish spots; the under parts are whitish. Total length only 1½
inch.
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