TRETANORHINUS.—ISCHNOGNATHUS. 135 
Regina nigrolutea, Cope, Bull. U.S. Nat. Mus. no. 32, p. 74. 
Helicops agassizii, Jan, Arch. per la Zool. iii. p. 254 (1865) ; Iconogr. Ophid. xxviii. t. 2. fig. 1. 
Helicops bifrenatus, Bocourt, Bull. Soc. Philom. viii. p. 184 (1884). 
? Tretanorhinus lateralis, Bocourt, Le Nat. 1891, p. 122. 
Hab. Nicaraeva (Cope); Panama (Mus. Brit.), Colon (Mus. Paris). 
2. Tretanorhinus dimidiatus. 
? Tropidonotus dimidiatus, Boie, Isis, 1827, p. 535. 
Tropidonotus dimidiatus, Cope, Proc. Ac. N. Se. Phil. 1862, p. 297. 
Regina dimidiata, Cope, Bull. U. 8. Nat. Mus. no. 32, p. 74. 
Hab. Mexico, Jalapa (Cope). 
This is an altogether dubious species ; and without the examination and comparison 
of the typical specimens described by Boie and Cope no opinion can be formed as to 
the correctness of Cope’s identification, or Boulenger’s view, according to which Boie’s 
snake is the Indian Atretiwm schistosum. Unfortunately, it is not known in what 
Museum Boie’s specimen is preserved, if it be still in existence; the example described 
by Cope was contained in the Museum of the Philadelphia Academy, but it cannot now 
be found there. 
3. Tretanorhinus mocquardi. 
Tretanorhinus mocquardii, Bocourt, Le Nat. 1891, p. 122. 
Hab. CENTRAL AMERICA. 
I have not seen a specimen of this species. 
HELICOPS. 
Helicops, Wagler, Nat. Syst. Amphib. p. 170 (1830). 
1. Helicops septemvittatus. 
Calopisma septemvittatum, Fisch. Verh. naturw. Ver. Hamburg, iii. p. 84, t. 1. fig. 3 (1879). 
Limnophis septemvittatus, Cope, Bull. U.S. Nat. Mus. no. 82, p. 75. 
Helicops septemvittatus, Bouleng. Cat. Sn. i. p. 275. 
Hab. Mexico. 
Unknown to me. 
ISCHNOGNATHUS. 
Ischnognathus, Dum. & Bibr. Mém. Ac. Sc. xxiii. p. 468 (1853). 
Storeria, Baird & Girard, Cat. N. Amer. Rept. 1853, p. 135. 
