300 PROCEEDINGS OF THE ACADEMY OF [April, 



margin of each bearing one prominent anterior lobe and several 

 posterior to this, the last one of which is considerably developed 

 in the first molar. Lower incisors small, uniform, bifid; lower 

 canines hastate, with an external l)asal shoulder; lower premolars 

 unequal, the first a simple cone, the second larger, with a posterior 

 shoulder; lower molars low, the anterior somewhat larger than the 

 posterior, the latter ranging from subquadrate to subtriangulate in 

 section, each bearing two low angulate cusps. 



Remarks. — It is evident that the species presents some diversity 

 in size and probably some in color, but it is quite as evident that 

 such variation is individual or sexual (the males ))eing on an aver- 

 age slightly larger than the female), and cannot be separated into 

 geographic forms. The single specimen from Costa Rica cannot 

 be separated from specimens from Vera Cruz, jNIexico, and the five 

 specimens (three males, two females) from ]Mirador present con- 

 siderable variation among themselves. 



The species described by Lichtensteiu and Peters ( C. flavogu- 

 laris) and Saussure ( C. mexicanus) can readily l)e jilaced as syno- 

 nyms of C senex, Peters afterward admitting such to be the case 

 with C. flavogidaris ; and Saussure' s C. mexieanus can be matched 

 with specimens of senex, the difference in color ])eing very likely 

 due to the length of immersion in the preserving fluid. The species 

 C. mcmurtrii H. Allen was based on the adult male," the folds 

 being in all px'obability secondary sexual characters. 



A close examination of the description of C. minor Ward shows 

 that the describer was probably misled by Dobson's description of 

 the chin folds, and in the absence of material for comparison he 

 described a female which agrees exactly with two females before me; 

 the discrepancies in measurement beng simply individual, while 

 the second lower premolar of all the available specimens is more 

 than half the size of the first and some are decidedly not triangu- 

 lar in section. The describer of C. minor stated that he would not 

 be surprised " if minor should eventually prove to be but a variety 

 of senex." 



Specimens Examined. — Sex'en: one skin, five alcoholics and one 

 odd skull. 



U. S. N. M., AWe, ale, Mirador, V. C, Mex. d. Coll. 

 Dr. C. Sartorius. Type of Centurio mcmurtrii H. Allen. 



^ " A fact quite evident on the examination of four males, one of which is 

 the type of the species. 



