1867.] MR. ST. GEORGE MIVART OX PLETHODON PERSIMILIS. G97 



found there, yet he fully expects that such will eventually he dis- 

 covered. Nevertheless, though the appearance of some American 

 tailed amphibians was thus rendered less unlikely, yet the appearance 

 of such a genus as Plethodon, which has no representative in Japan, 

 was somewhat startling, and I therefore examined the specimens 

 with great interest and as carefully as I could. 



Dr. Giinther, as before said, has detected several differences be- 

 tween PL glutinosus and the species under consideration ; he gives 

 the distinctions thus : — 



"PL glutinosus. PL persimilis. 



Limbs feeble. Limbs well developed. 



The length of the fore limb is The length of the fore limb is 



considerably less than one-half of one-half the distance between the 



the distance between fore and fore and hind limbs, 

 hind limbs. 



The length of the hind limb is The length of the hind limb 

 one-half of the distance between is considerably more than one- 

 fore and hind limbs. half of the distance between fore 



and hind limbs. 



The third and fourth toes are The length of the third and 



much shorter than the cleft of fourth hind toes equals that of 



the mouth. the cleft of the mouth. 



Trunk with thirteen lateral Trunk with twelve lateral cross 



cross folds. folds. 



Tail subcylindrical at the base. Tail compressed at the base. 



Tongue large, covering the Tongue narrow, elliptical, not 



whole bottom of the mouth, its covering the whole width of the 



hiud margin being free. bottom of the mouth, without 



free posterior margin. 



The series of palatine teeth is The series of palatine teeth is 



distinctly interrupted in the subcontiuuous. 

 middle. 



" In other respects both species are very similar, the Siamese form 

 being black, with small scattered whitish spots." 



In addition to these differences, I find that the Asiatic species is 

 entirely destitute of sphenoidal teeth, which, on the other hand, are 

 characteristic of the genus Plethodon. The species which un- 

 doubtedly belongs to the latter genus have, moreover, the first digit 

 of each extremity extremely short, which is not the case with P. 

 persimilis of Gray. Finally, in the Asiatic species (P. persimilis) 

 the phalanges of the manual digits (counting from the radial to the 

 ulnar side) are 2, 2, 3, 2 respectively, and the pedal digits (counting 

 from the tibial to the peroneal side) have 2, 2, 3, 4, 2 phalanges ; 

 while in Plethodon glutinosus the numbers are 1, 2, 3, 2 in the 

 manus, and 1, 2, 3, 3, 2 in the pes. 



These differences, when taken into consideration with the peculiar 

 geographical conditions, fully warrant the generic separation of the 

 species now under consideration from the Plethodon glutinosus, 



Proc. Zool. Soc— 1807, No. XLY. 



