450 DUNN. 



The larvae of both species of Onychodactylus possess claws, and these 

 are present also in the breeding adults of the Japanese species. 



The tail varies from short and thick, to very flat, and to long and 

 slender. H. kimurai offers the extreme development of the first type; 

 Ranodon, Batrachwperus, Pachypalaminus, H. mndcnburghi, and H. 

 retardatus are examples of the second; Onychodactylus has the third 

 type of tail. 



H. leechii and its allies with a moderately long tail, cylindrical at 

 the base, and flattened towards the tip, perhaps represent the primitive 

 tail form. The proportionate length of the tail increases with age. 



The larvae of Hynobius and of Batrachupcrus have a dorsal fin on 

 the body. This is not present in larvae of Onychodactylus, the fin 

 being restricted to the tail, and as this is the case in most mountain 

 brook forms, it is probably confined to the tail in Ranodon also. 



The gill filaments or fimbriae of Hynobius larvae arise from the 

 ventral edges of long filament bearers or rami. These are very short 

 in Onychodactylus larvae and absent in larvae of Batrachupcrus so that 

 the filaments seem to arise directly from the dorsal part of the septum. 



Onychodactylus has no lungs. The other forms have the lungs well 

 developed. However, the ypsiloid cartilage, so generally lacking or 

 aborted in lungless salamanders is normally developed in Onycho- 

 dactylus. 



The tongue is sessile, but free at the lateral and posterior edges, 

 save in Batrachupcrus, where it is very small, apparently not free at 

 the edges, and seems to be retractile into a sort of sheath. The 

 hyobranchial skeleton of Batrachupcrus does not differ from that of 

 Hynobius. 



Males of the family lack the papillae which line the cloaca in males 

 of Ambystomidac, Salamandridac, Plcthodontidac, Protcidac, and 

 Amphiumidac, and which secrete the spermatophores by means of 

 which internal fertilization is accomplished in these families. The 

 spermatheca, found in females of the families just mentioned, is lack- 

 ing in females of the Hynobiidac. In both male and female characters 

 the Cryptobranchidac agree with the Hynobiidac. The fertilization of 

 the former is well known to be external. The fertilization of the 

 latter is known from two observations (Dybowski 1870, H. kcyscr- 

 lingii; Kunitomo 1910, H. ncbulosus) both of which indicate external 

 fertilization; and these, together with the anatomical evidence, may 

 well mean that this method is in vogue throughout the family. 



The vent of female Hynobius is a simple longitudinal slit; but males 

 of this genus, probably at the breeding season, develop additional 



