NATURAL SCIENCES OF PHILADELPHIA. 79 



79. C. amoena nobis. Coluber amaenus Say, Jour. Acad. Nat. Sci. iv. 

 237. Calamaria amoena Schl. Ess. Phys. Serp. 31. Brachyorrhos amoenus 

 Holbr. Am. Herp. iii. 115. Carphophiops vermiformis Gervais, Diet. Univ. 

 d'Hist. Nat. iii. 191. Carphophis amoena Dum, & Bibr. vii. 131. Celuta amoe- 



Catal. Rept. p. 127. 



This genus is characterized by the elongated form of the shields of the head, 

 and the distinctness of the latter from the body. There are two small nasal 

 plates, as in Rhabdosoma. 



80. V. V a 1 e r i a e Bd. & Grd. 1. c. 



One specimen, ? ? 



Homalosoma Wagl. Type H. 1 u t r i x. 

 Nat. Syst. Amph. 190, 1830. 



81. H. lutr ix D. fr B. vii. p. 110. 



Two specimens, Cape of Good Hope, Garden of Plants. 



Oligodon Boie. Type 0. subquadratum. 

 Isis 1827, p. 519. 



82. O. sublineatum Z).&B. vii. p. 57. 



One specimen, Ceylon, Mr. Cuming. 



Genera 11. Species 18. Specimens 54. 



The stoutness of the body and tail, and the shortness of the latter, the in- 

 distinctness of the head, and the general firmness and rigidity, are characters 

 by which the greater number of the species of this sub-family may at once be 

 recognized. But as in some genera, certain of these peculiarities vanish, thus 

 approximating them to other groups, we have followed M. Dumeril in employ- 

 ing the dentition, which is here quite characteristic. Elsewhere, however, it 

 evidently fails to characterize natural groups, as urged by Dr. Giinther in his 

 invaluable catalogue of the Colubrine snakes in the British Museum. We 

 have, therefore, omitted the genera Rhinostoma, Phimophis* and Homalo- 

 cranion, which have the posterior superior maxillaries grooved, and are perhaps 

 more nearly allied to Scytale. A single specimen of Scytale coronatum, 

 of a variety near that called S. Neuwiedii in the Erpetologie Generale was 

 described by us, Proc. of this Acad., 1859, p. 294, as Olisthenes euphaeus. 

 Our conviction of its generic distinctness was grounded upon the peculiar form 

 of the rostral plate, which while offering strong characters among some ser- 

 pents, here varies with the individual. 



* Phimophis G u e r i n i , the only species. It is Rhinosimus G u e r i n i of Dumeril and 

 Bibron, but the generic name was applied to certain species of Curculionidae, by Latreille, 

 more than fifty years previously. 



I860.] 



