THE SNAKE GENUS TRIMORPHODON — SMITH 157 



an additional, smaller, terminal flounce is not readily discernible in 

 noneverted liemipenes). In addition it may be observed that tbe 

 hemipenis is 16 to 20 caudals long (in situ) and that the flounces are 

 relatively small, near the tip, and cover a length equal to the length 

 of four or five caudals. 



Specimens examined show constant differences in head and neck 

 pattern from larnhda. In lyrophanes the dark, V-shaped mark (which 

 extends nearly or quite to a line even with posterior border of orbits) 

 extends posteriorly onto the neck, without a break; in lambda it 

 extends posterolaterally and terminates a little posterior to the labials, 

 about even with a line drawn back from the lip. The light band 

 posterior to this dark band in lyrophanes continues onto the neck and 

 terminates with a large neck blotch, or else its arms unite posteriorly 

 and may pierce the neck blotch posteriorly; in lambda this mark 

 extends posterolaterally and usually unites with the white of the 

 ventral surface. 



A difference in the character of the dorsal blotches in lyrophanes 

 and lamhda is evident to the eye but is not well suited to measurement. 

 The blotches are narrower and longer in lyrophanes^ and fairly well 

 severed from their lateral extensions ; they are broader and shorter in 

 lamhda. and their lateral extensions are not so strongly differentiated. 



TRIMORPHODON VANDENBURGHI Klauber 



Trimorphodon vandenhuryhi Klauber, Bull. Zool. Soe. Sau Diego, No. 1, 

 pp. 17-18, fig. 3, 1924 (Wildwood Ranch, 1,520 feet, 5 miles southwest of 

 liamona, Sau Diego County, Calif.) ; Trans. San Diego Soc. Nat. Hist., vol. 

 5, pp. 183-194. pis. 22. 23, 1928; vol. 9, pp. 169-180, pi. 7, fig. 1, 1940. 



Diagnosis. — Large V-shaped marks on head, these usually not con- 

 tinued on neck ; hemipenis short, without spines ; ventrals 244 or less ; 

 anal entire. 



Specimens examined. — One. 



Locality records. — Numerous localities in southern California (see 

 Klauber, op. cit., 1940). 



Remarks. — A single hemipenis examined in situ agrees ^vith the 

 description given by Klauber {op. cit.. 1940, p. 170), with the excep- 

 tion that only three flounces are discernible (instead of four). In 

 addition, the hemipenis is 14 caudals long and the flounces are rela- 

 tively small, as in lyrophanes. 



This very distinct species appears to be directly related to lyro- 

 phanes. Its chief difference from the latter — ^the entire anal — is an 

 amazing development in a genus with so few structural variations. 



TRIMORPHODON BISCUTATUS QUADRUPLEX, new subspecies 



Holotype.—V. S. N. M. No. 89476, female, Esteli, Nicaragua, col- 

 lected by J. H. Ivy in 1932. 



408590 — 41 2 



