1886.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 1 89 



debted to M. Diaz for the orgauizatioii and successful conduct of the 

 Comisi.on. 



This species has been figured and described by M. Bocourt as the 

 Toluca lineata of Kennicott, from which it differs in various respects, 

 one of which refers it, in my opinion, to another genus. Besides the 

 typical species of Chionactis and the C. occipitalis Ilallow. from Arizona, 

 there are two species of Ogmius (Cope) which considerably resemble the 

 Chionactis diasii. These are the 0. varians Jan. and a new species which 

 I call 0. acutus. Before describing the latter I compare three Mexican 

 species, as follows : 



I. Rostral plate slightly concave above. 

 Occipital plates divaricate posteriorly; a dorsal series of spots; 0. 

 varians Jan. 



II. Rostral plate flat or convex above. 

 Occipitals rounded without notch behind; five longitudinal bands; ros- 

 tral less acute; C. diasii Cope. 

 Occipitals rounded ; a series of dorsal transverse spots ; rostral acute 

 angled ; 0. acutns sp. nov. 

 The 0. acutus was sent to the National Museum, by Sumichrast, from 

 Tuchitan, on the Pacific side of the isthmus of Tehuautepec. It nearly 

 resembles the C. diazii in all important respects, but has the rostral 

 plate produced to an acute point. The coloration is totally different, 

 resembling rather the 0. varians. It consists in the tyi)e specimen of 

 sixty-one black transverse spots of one scale in length and three to 

 five scales width, separated by interspaces of a scale and a half in 

 length. Sides, abdomen, and head, including lips, unspotted. Gastro- 

 steges, 127 ; anal, 1-1 ; urosteges, 32. Total length, 249°'™ ; of tail, 40'»°i; 

 of head, lO-^'"'.— E. D. Cope.] 



42. Tantilla calamarina Cope. 



TantiUa calamarina Cope, Proc. Acad. Phila., 1866, 320. 

 Vulg. — Culebra. 

 Hab. — State of Puebla. Teziutlan, No. 49, December. 



43. Rhabdosoma semidoliatum Dum^ril et Bibrou. 



lihabdosoma semidoliatum Duni6ril et Bibron, Erp6t. g^u., VII, 1, 1854, p. 93. 

 Vulg. — Culebra, Coralillo. 



Rah. — State of Vera Cruz. Misantla, Nos. 51, 52, 53, 54; Jalapa, No. 

 297. 



44. Rhabdosoma longiceps Cope, sp. nov. 

 Vulg. — Culebra negra. 



Eab. — State of Vera Cruz. S. Jose Acateno, No. 301 type. 



[This snake possesses all the principal characters of the 22. mutitorques 

 Cope (Proceedings Amer. Philos. Soc. 1885, p. 385), but differs from the 

 dozen or so of that species now in my collection by a constantly more 

 elongate head and scuta, especially the i)refrontals and superior labials. 



