THE SNAKE GENUS TRIMORPHODON — SMITH 159 



Variation. — The paratypes available are in such poor condition 

 that the number of blotches cannot be counted, but they are of the 

 same nature as in the type. The scale characters of Nos. 5569, 6805, 

 and 32274, respectively, are: Scale rows 25-25-17,?, 23-25-?; ventrals 

 255, ?, ? ; caudals 92 ( ^ ), 93 ( 5 ), 90 ( 5 ) ; supralabials 9-9, preocu- 

 lars 3-3, postoculars 3-3, in all; infralabials 13-14, 13-14, 12-13; 

 loreals 3-3, 2-3, 2-3; preocuiars separated from frontal on one side 

 in one. 



Comparisons. — The present form differs from hiscutatus solely in 

 the extent of subdivision of the blotches, which in this are very com- 

 plex, consisting of two halves (each of which appears like the pri- 

 mary blotches of hiscutatus) , which again are partially divided. 

 For practical purposes of separation from biscutatus, the blotches 

 may be considered separately, whereby the number secured is much 

 greater than the number of primary blotches in biscutatus. 



TRIMORPHODON BISCUTATUS BISCUTATUS (Dumeril and Bibron) 



Dipsas iiscutata Dumeril and Bibron, Erpetologie geuerale, vol. 7, p. 1153, 1854 



(Mexico). 

 Trimorphodon major Cope, Proc. Amer. Philos. Soc, vol. 11, p. 153, 1869 (Tehuau- 



tepec). 



Diagnosis. — ^Large V-shaped marks on head ; dorsal blotches 18 to 23 

 on body, separated from one another by a distance at least a little 

 greater than half their own length (usually equal or greater) ; a sec- 

 ondary, transverse, broken, narrow, black band between each pair of 

 primary blotches (rarely reduced to lateral spots; in this case the 

 primary blotches do not close the large space between the primary 

 blotches) ; ventrals 251 to 275 ; caudals 81 to 102 ; total counts 343 to 

 376. 



Specimewi examined. — Twenty-four. 



Locality records. — ^Acceptable records are from the Isthmus of 

 Tehuantepec (Santa Efigenia, El Barrio, Tres Cruces, Tehuantepec, 

 Cerro Guengola, La Concepcion) in the State of Oaxaca; Tonala and 

 San Eicardo in Chiapas; Huajintlan, Morelos; Agna del Obispo, Or- 

 ganos, Acapulco, and La Crucita, Guerrero; and Hda. El Sabino and 

 10 miles north of Tafetan, Michoacan, 



Remarks. — A specimen from Tehuantepec has a hemipenis 24 

 caudals long; flounces 3, large, covering a length equal to about 7 

 caudals ; area of spines covering a length of 4 or 5 caudals. 



As pointed out by Taylor,^ northern specimens have higher average 

 ventral and caudal counts than southern specimens. Present speci- 

 mens are insufficient, however, to show whether the differences are 

 significant and practically recognizable. The counts are given in 

 table 1. 



» Kan.sas Unir. Sci. Bull., vol. 24, pp. .^58-360, 1939. 



