THE CHARACTERS OF THE GENUS GEOCAPROMYS 



CHAPMAN 



By GERRIT S. MILLER, JR. 



curator, division of mammals, u. s. national museum 

 (With One Plate) 



In his " Revision of the Genus Capromys " (Bull. Amer. Mus. Nat. 

 Hist., Vol. 14, pp. 313-323, Nov. 12, 1901) Mr. Frank M. Chapman 

 established a sub-genus Geocapromys (p. 314) to include Capromys 

 hrownii J. B. Fischer, C. thoracatus True and C. ingrahami J. A. Allen, 

 animals that were supposed to have skulls and teeth essentially like 

 those of the species of true Capromys, but to have unusually short 

 tails and poorly developed thumbs. Sixteen years later Dr. Glover M. 

 Allen raised Geocapromys to generic rank and added to its characters 

 the presence of a small supplemental reentrant angle near the front 

 of the lingual side of the first mandibular molariform tooth (Bull. 

 Mus. Comp. Zool. Vol. 61, p. 9, Jan., 1917). In 1919 Mr. H. E. 

 Anthony noticed that the course of the upper incisor of Geocapromys 

 is clearly shown on the face of the maxillary as a prominent swelling 

 on the wall of the antorbital foramen, while in Capromys no such 

 swelling is present (Bull. Amer. Mus. Nat. Hist., Vol. 41, p. 631, 

 Dec. 30, 1919). In his 1917 paper Dr. Allen, misled by Chapman's 

 imperfect specimens of Geocapromys columbianus, made his own 

 better material of the Cuban animal the basis of the new name G. 

 cubanus (p. 9), and proposed (p. 5) the generic name Synodontomys 

 for the original C. columbianus. These errors he later recognized and 

 corrected (Bull. Mus. Comp. Zool., Vol. 62, p. 145, May, 1918). 

 When preparing the copy for my " List of North American Recent 

 Mammals 1923 " I concluded that the dental features pointed out 

 by Allen and Anthony did not warrant the generic separation of the 

 group from Capromys. Not knowing of any other characters I 

 relegated Geocapromys to subgeneric rank again. More recently, while 

 examining broken skulls from caves in Cuba, I found that there are 

 important and constantly present features of both skull structure and 

 tooth arrangement that fully justify the generic separation of the 

 two groups. The diagnostic characters may be tabulated as follows : 



Smithsonian Miscellaneous Collections, Vol. 82, No. 4 



