462 DR. J. E. GRAY ON DACTYLETHRA. [Nov. 8, 
home by Mr. Walker were not the young of the common Dactylethra 
(an opinion that I entertained myself when I first saw them, and until 
I had compared them with the papers on the subject), I have been 
induced to reconsider the question, and to study the genus. This 
study has led me to the conclusion that the two geographic species 
of Dactylethra are but one, which is spread over the whole of South 
and Western Africa; and also to retain the opinion tnat I have pub- 
lished, that the specimens brought by Mr. Walker from Lagos are 
probably of a distinct form. I will not take on myself to deny that 
they may not be the larva of Dactylethra, as the larva of that genus 
and the adult form of Si/urana are unknown; but even if it is proved 
hereafter that they are only the larva of Dactylethra, I think that 
it is better for the present to keep them separate, until the change 
from one state to the other has been observed and recorded, and, 
at all events, that the description and observation of the larva is an 
important addition to the history of the genus. 
It would be a remarkable change, if the large beard that is placed 
at the angle of the mouth in one genus should turn into the minute 
beard on the lower edge of the orbit, far above and in front of the 
angle of the mouth, in the other ; yet I am assured by an experienced 
herpetologist that he believes that this change does take place, and 
that it is only consistent with what is to be observed in the transfor- 
mation of other Batrachians. No such changes have occurred to 
me. There is no doubt that the beard at the angle of the mouth is 
much longer and more slender in the young larva than it is in the 
oldest specimen we yet possess of the genus Silurana. But while 
the beard diminishes in length, it increases considerably in thick- 
ness, showing no inclination to disappear, and does not at all alter 
its place in any of the specimens I have observed either in the British 
Museum or at Liverpool. 
The least-developed fish-formed specimen (fig. 1) is about 23 inches 
long, and has only the hinder pair of legs developed. The legs are 
short and weak ; and the toes are short and of nearly equal length, 
but with the three black claws well developed. The head is de- 
pressed, very broad and flat above, and shelving to near the back 
behind. The mouth is small, with a very long slender beard on the 
upper lip, at the angle of the mouth. The eye is on the keel on the 
side of the head, considerably behind the beard, placed so as to be 
visible from the upper and lower surface. The body is swollen ; 
the tail compressed; the inferior fin commences in the middle of 
the belly, and is extended to the end of the tail. 
There is a second fish-formed specimen, not more than 2 inches 
long and much more slender, which also has the front limbs developed, 
from the upper part of the sides; these limbs are weak, and the toes 
are short and equal. The hinder limbs are rather more developed, 
their toes rather more unequal ; and the fin on the under part of the 
body and tail is also broad and more membranaceous. The mouth, 
beard, and eyes are exactly as in the former specimen. 
The other two specimens (fig. 2) have assumed the form of the 
genus Dactylethra, having both the fore and hind limbs well deve- 
