202 BULLETIN 17 7, UNITED STATES NATIONAL MUSEUM 



Genus LEIOCEPHALUS Gray 



1827. Leiocephalus Gray, Philos. Mag., ser. 2, vol. 2, p. 207 (type, L. carinatus). 



1837. Holotropis Dumeril and Bibron, Erpetologie generate, vol. 4, p. 259 (same 

 type). 



1838. Pristinotus Gbavenhorst, Nova Acta Acad. Caes. Leop.-Carol., vol. 18, 

 pt. 2, p. 738 (type, P. schreibersii) . 



1843. Steironotus Fitzinger, Systema reptilium, p. 70 (type, S. schreibersii) . 

 1862. Liocephalus Cope, Proc. Acad. Nat. Sci. Philadelphia, 1862, p. 182 (emend.). 



This genus is one of the most complex of those occurring on His- 

 paniola. The presence of an unexpectedly large number of quite 

 definite subspecies belonging to the personatus group proves that the 

 island has been the scene of drastic geographic changes, which have 

 tended to isolate portions of it at one period as islands, perhaps to 

 reunite them with the mainland as peninsulas at a later date. 



Two primary stocks of Leiocephali occur in Hispaniola. The one 

 to which I have just referred, represented here by the personatus group, 

 contains the big-scaled, bristling lizards without a lateral fold, the 

 lateral scales having nearly the same slant and size as the dorsolaterals. 

 The other stock, to which both melanochlorus and schreibersii belong, 

 dissimilar in other respects as they may be, is characterized by the 

 presence of a lateral fold, the scales on the sides of the body being 

 therefore much different in size and direction from the dorsolaterals. 



The description of the various subspecies of personatus on His- 

 paniola is probably not yet complete, as additional collecting from 

 many hitherto unvisited regions will undoubtedly show in the future. 

 The forms herein discussed are readily defined even with the rather 

 scanty material at hand. Some of the obvious relationships may be 

 summarized here. 



In color pattern semilineatus and beatanus apparently are somewhat 

 similar, as the wide dark lateral stripe is found in both, together with 

 an almost complete suppression of cross bands. The throat and 

 breast are immaculate in semilineatus but heavily spotted in beatanus. 



A similarity also exists between mentalis and scalaris, in which the 

 adult males are characterized by a nearly uniformly colored body, all 

 the contrasting pigment being concentrated on the sides of the head, 

 where white spots appear to interrupt and emphasize the dark area. 

 The chin is heavily spotted. The true personatus from the extreme 

 southwestern peninsula resembles both mentalis and scalaris but goes 

 one step farther in intensifying the dark color on the sides of the head 

 by extending it farther back on the neck and in addition well onto the 

 chin, while there is no interruption by light spots. Like the other 

 two forms, the body of the adult male personatus shows very little 

 pattern. L. barahonensis appears to belong in the group with 

 mentalis and scalaris. 



