NATURAL SCIENCES OP PHILADELPHIA. 73 



E. Gravenhorstii Jan, loc. cit. p. 524, resembles this species, but has 

 a black half-collar only, and a longer tail. The preocular is very small, sepa- 

 rated from the nasal by the contiguous post-frontal and superior labial. In 

 our species the preocular is unusually large, and in contact with the nasal. 



Species 53. The three specimens here referred to frontalis D. B. belong 

 to a species nearly allied to lemniscatus, apparently undescribed. The 

 most prominent differences are, the exact equality of the black rings in width, 

 the shorter intervals between the triads, and the position of the first ring 

 which touches the occipital and last labial shields. In lemniscatus, its 

 vars. frontalis and baliocoryphus, in Marcgravii and deco- 

 ra t u s , the first black ring is several scales behind the angle of the mouth, 

 the intermediate space being red ; also the central ring of each three is wider 

 than the external. Distance between the middle and outer of the three rings 

 in our specimens of lemniscatus two and three scales ; inisozonus 

 (as we now call this serpent) four. In the former the anterior part of the 

 occipitals is crossed by a black band ; in the latter they are entirely white, 

 (red ?), except a little black at the posterior ends. 



E. isozonus nob. Sets of rings twelve. No. 1, gastrosteges 201 ; anal 1, 

 entire ; urosteges 28, first 9 entire. No. 2, 218 ; anal 1, divided ; urosteges 26. 

 No. 3, 213 gastrosteges ; anal 1, divided ; urosteges, 29, two entire. We do 

 not know the part of South America inhabited by this serpent. 



Species 54. The specimen here described as Elaps baliocoryphus is, 

 as we now believe, a variety of the lemniscatits. It resembles the figure 

 of the var. frontalis D. $ B. ("Marcgravii" Pr. Max.) in Abbild. 

 Naturgeschichte Brasiliens, differing in having an additional red (white) band 

 across the fronts of the occipitals. Whether Marcgravii D. $ B. be a 

 variety of lemniscatus, as believed by Dr. Giinther, or not, the latter is 

 certainly liable to great variation in the distribution of colors on the head. 



In place of E. baliocoryphus, insert 



54. E. filiformis Giinther, Proc. Z. S.1859, p. 86. 



The head of our specimen is so badly mutilated that the characters could 

 not be made out without difficulty. We are, however, much gratified to be 

 able to record our probable possession of the interesting species described as 

 above. It may be known from other American Elapses by its excessively 

 elongate form and the possession of but one postocular. In a few particulars 

 it differs from Dr. Giinther's description. The nasal plates are two : two tem- 

 porals bound the upper border of the sixth labial shield, the anterior of which 

 reaches the postocular. There is no light-colored band across the post-frontals. 

 Triads of rings nineteen, disposed as in the description. 



Preocular acute anteriorly, just touching the nasals ; hence the post-frontals 

 are bent down, and almost reach the labials. Third, fourth and fifth superior 

 labials narrow and high, eye resting on the suture of the last two. Gastros- 

 teges 308 ; anal 1, divided ; urosteges 42. Length 21 in. 9 1. 

 One sp. ? Dr. Wilson. 



To assist further in the identification of the species of Elaps having the rings 

 arranged by threes, we have prepared the following table. Those marked with 

 an asterisk are not in the Museum of the Academy. 



A. Postoculars two. 

 Head compressed, lanceolate. 

 Labials not reaching the occipitals. altirostkis Cope. 



Head depressed. 

 Sixth superior labial reaching the occipital. *decoratus Jan. 



Sixth superior labial not reaching the occipital. 



f Posterior part of occipitals included in a black collar or half-collar, 

 a. Neck surrounded by a narrow yellow ring. 



I860.] 



