1905.] ABNORMAL RANID LARV^. 59 



these have been submitted to Mr. G. A. Boulenger, whom I have 

 asked to add a note as to their identity. I need only say that 

 they appear to belong to the genus Rana *. My observations are 

 of necessity confined to the external appearance and osteological 

 characters of the abnormal specimens, with a general considei-ation 

 of theii- visceral anatomy, for their muscular tissues ai'e too 

 decomposed for proper investigation. Even cartilaginous struc- 

 tures have degenerated greatly. 



As regai'ds visceral anatomy, the more advanced of the two 

 tadpoles (which I shall call A) has an alimentary canal resembling 

 that of a young frog, well- developed and apparently healthy. 

 The tongue and palate are as in an adult. The lungs are large, 

 extending nearly to the posterior end of the body-cavity ; the 

 kidneys seem to be normal, but I cannot trace any part of the 

 generative system. The heart and larger blood-vessels are 

 apparently normal. The condition of the viscera is less advanced 

 in the other specimen (B), in which the mouth is that of a 

 typical Ranid lai'va, except that there are no horny teeth. The 

 intestine is still coiled in a spiral, and the lungs are small. 



It is in the structure of the limbs and axial skeleton that the 

 main abnormalities are found in both specimens. Figs. 1, la, 2, 

 2 «, of PL YI., show that there is no hind limb in either specimen, 

 and that while the fore limbs are well-developed in A, they can be 

 seen through the skin in B. 



The dimensions of the two specimens are : — 



A. B. 



mm. mm. 



Total length 78 82 



' Snouttovent 42 28 (ap.). 



Tail 35 54 



Right arm 30 16 



Left arm 25 17 



Before dissecting A, I was led by deceptive appearances to 

 believe that the hind limbs were developed beneath the skin, and 

 I have to thank Mr. G. A. Boulenger for suggesting a further 

 examination, which showed that I had been wrong in this belief, 

 A dissection of the pelvic region led to an examination of the 

 skull and vertebral column of A ; in B I could find very little, 

 owing to the fact that its skeleton had been chiefly cai'tilaginous. 



Although the head of A looked like that of a young frog, the 

 lower jaw was quite unossified and soft, and the cranium was in a 

 very simple condition. The cranial box was well ossified above 

 and on the sides, the bone being stout and sculptui-ed on the 

 surface. Its floor was represented by a delicate membrane, 

 through which the I'emains of the brain could bo seen. Below 

 this, but not in close contact with it, lay a large, well-ossified 



* [They arc uudoubtcxllj^ referable to Baiia alticola Blgr., of which larvie are 

 tiu-uved in the Brit. Mus. Catalogue of Batrachia Ecaudata, p. 63. — G. A. B.] 



