276 PROF. G. B. HOWES ON THE DETELOPMENT OF THE [Mar. 14, 



inversion in growth is interesting, as it tends to bring the Am- 

 phibian " coccyx " into closer harmony with that of the Mammal, 

 in which (Homoy ossification of the vertebral arches, unlike that 

 which obtains in the pre-sacral region, is effected subsequently to 

 that of their overlying centra ^ 



It may be of interest here to recall the similarity in numerical 

 reduction of the free vertebra; met with in the Anurous Amphibia 

 (Pi^ja to 7) and the Teleostean Yishes {Ostrudon to 14) ^ In its 

 occasionally rod-like character, the Teleostean " terminal vertebra " 

 may so closely approximate to the condition of the Amphibian 

 urostyle (ex. Molva) as to merit that title ; and the enclosure 

 within it of a cartilaginous urochord (ex. Osmerus) indicates a close 

 parallelism of modification between the frn'O great groups of Ver- 

 tebrates, which calls for further investigation. 



Cartier has directed attention ^ to an apparent similarity in the 

 primary mode of origin of the vertebral bodies of Urodeles and 

 Teleostean s ; and the interest of the foregoing consideration is 

 enhanced by the discovery by Emery ^ and Albrecht * of an odon- 

 toid vertebra of the Amphibian type in Fierasfer, Pelanu/s, and 

 certain other bony fishes '', and by the tendency towards a common 

 type of fusion of vertebrae in the two great groups ^ 



Pedal SJceleton. — An adult male of the Spotted Salamander 

 (S. maculosa) has recently come into my hands in which the hind 

 limb was exceptionally modified (figs. 15 & 16) ; and as it is the 

 only one possessed of a reduced pedal skeleton out of some hundreds 

 which have from time to time come under my notice, I conclude 

 that the variation of the same is, in this animal, very rare. 



The left hind limb (fig. 15) was in every respect normal ; but 

 the right one (fig. 16), when viewed externally, appeared to be 

 tridactyle. The apparent three digits were less completely dis- 

 tinct from each other and less freely movable than those of the 

 normal limb, and the presumed inner one (I, II), which was very 

 short, and in transverse diameter equal to the other two combined, 

 was more rigid than the rest of the limb and apparently of little 

 service in progression. When the limb was brought to the ground, 



'^ Especially wlien regarding as coccygeal those so-called sacral vertebrsb 

 which take no share in the formation of the ihac articulation. 



2 Cf. Quain's 'Anatomy,' ed. 9, pp. 20-22. 



3 aiinther, ' Introd to Study of Fishes,' p. 686. 



^ Zeitsclir. f. wiss. Zool. Bd. sxxv. (Sup.) p. 73 ; cf. also Goette, loc. cit. 

 p. 415. 



5 Fauna u. Flora d. Q-olfes von Neapel, Monogr. ii. p. 26 (1880). 



e Loc. cit. p. 472. 



■^ The analogy, if worth anything, certainly does not bear out Jordan's recent 

 suggestion (Proc. U. S. Nat. Mus. vol. xiv. p. 107) that this numerical reduc- 

 tion and its associated " ichthyization," as he somewhat fantastically terms it, 

 take place in degree approximate to the approach to the equator. 



" Cf. Schmidt, he. cit. p. 757. 



