NATURAL SCIENCES OF PHILADELPHIA. 101 



Costal plicae 17 ; elongate, head narrow, width more than seven times to 

 groin, more than twice to axilla; no canthus rostralis ; tail compressed from 

 base, finned; small; pale yellow, brown lined S. m a r g i n a t u m. 



Stereochilus marginatcm Hallowell. 



Pseudotriton marginatus Hallowell, Proceedings Ac. Nat. Sci. Phila. 1856, 

 p. 130. 



MANCULUS Cope. 



Tongue free all round, boletoid. Toes 4 — 4. Parietal bones ossified, and 

 without fontanelle. Premaxillaries co-ossified. 



This genus only differs from Spelerpes in the absence of a digit from the 

 hind foot, standing thus in the same relation to it that Hemidactylium does to 

 Plethodon. Its only species was formerly referred to Batrachoseps, but besides 

 the great difference in the tongue, the latter has a parietal fontanelle and lacks 

 the prefrontal bone. The latter point is indicated by Eschscholtz in his Atlas. 

 In the present genus that bone is present; 



But one species is as yet known, which has a limited distribution. It is the 

 smallest North American Salamander. 



Manculus quadridigitatus Holbrook. 



Salamandra quadridigitata Holbrook, N. Amer. Herpetology, 2d ed. v, 65, 

 tab. 21. Batrachoseps quadridigitahis Baird, J. A. N. Sci. Phila. 1842, p. 287 ; 

 Gray, Catal. Brit. Museum, 1850; Hallowell, J. A. N. S. Phil. 1858, p. 348. 



South East Georgia. 



OPHEOBATRACHUS Gray. 



Annals and Magazine Nat. Hist. 1868, p. 297. Spelerpes Spec. Cope, 1865. 

 (Edipina Keferstein, Archiv. fur Naturgeschichte, 1868, 299. 



This genus differs from Spelerpes in the larval character of the cranium ; 

 its diagnosis is as follows: 



Tongue free all round, boletoid. Digits 4 — 5, very short, distinct. Sphe- 

 noidal series of teeth not united. Cranium membranous above, parietal bones 

 separated, scale-like. Internal nares enclosed except at the external fissure. 



Gray gives the generic name to the 0. v e r m i c u 1 a r i s, on account of its re- 

 markable vermiform shape. This is, however, among animals with reduced 

 limbs, always a more or less variable character, and when constant in a species 

 is certainly not of higher value. The relative elongation of the body and tail 

 is a marked specific character in Amblystoma, Plethodon and Spelerpes, and 

 in many Lacertilian genera, e. g. Gerrhonotus. It distinguishes species other- 

 wise nearly identical, and in some cases, as in G. mul t i car inat us, mere 

 varieties of the same species. 



The species of this genus are very similar to those of Spelerpes in all respects ; 

 the difference is not quite the same as that between Batrachoseps and Hemi- 

 dactylium. They are weak and of small size. The type species are distin- 

 guished by elongate tails. None are known outside of the Mexican zoological 

 district, in the broad sense. 



The generic characters were first indicated by the writer in the Journ. A. N. 

 Sci. Phila. 1866, p. 100. 



Costal plicae fourteen 0. lineolus. 



Costal plicas nineteen 0. ve r m icu 1 ar i s. 



Opheobatrachos lineolus Cope, 



Spelerpes lineolus Cope, Proc. Ac. Nat. Sci. Phil. 1865, 196. 



Char. Fourteen costal plicae ; vomerine teeth in long series, extending behind 

 internal nares ; tail twice as long as head and body, cylindric. Three median 

 toes, subequal. 



Though the carpus and tarsus in this species are cartilaginous, the repre- 



1869.] 



