04 General Notes. 



THE GENERIC NAMES CERCOMYS AND PROECHIMYS. 



In a paper published in 1899 Dr. J. A. Allen* reviewed the generic 

 name- Echimys and Loncheres, and after showing that the name Echimys 

 is inapplicable to the group containing Echimys cayennensis and other 

 species he proposed Proechimys, instead, with Echimys trinitatis as type 

 lie seems, however, to have overlooked the genus Cercomys F. Cuvier,t 

 which dates from 1829. The original description of Cercomys is accom- 

 panied l>y a plate illustration of an animal of the type currently recog- 

 nized as Proechimys; but more reliable evidence of the identity of these 

 genera is afforded in the illustrations of cranial characters published by 

 Cuvier* in contrasting Cercomys with other genera in 1832. The skull 

 figured is that of a young individual with the 3d upper molar not yet in 

 place. In the lateral view the angular process is missing, doubtless hav- 

 ing been broken off, and the imperfect nasals are indicated by a dotted 

 line. The rnolariform teeth are well shown, and the resemblance to 

 Proechimys trinitatus at the same stuge of development is very striking. 



The similarity of Cercomys and a spiny rat of this group in crania! 

 characters was noted by ( runther,§ who in describing Echimys brevicauda, 

 says: "The skull and dentition appear to differ scarcely from those of 

 Cercomys cunicularius and Echimys cayennensis." Careful comparison 

 of museum material with the descriptions and illustrations of F. Cuvier 

 convinces me that Cercomys cunicularius and Proechimys trinitatis are 

 congeneric, and that Cercomys should replace Proechimys as the generic 

 name at least for the species having three enamel islands in the crowns 

 of the first and second upper molars. In many forms this number of 

 enamel islands is normally present in these teeth and has apparently be- 

 come a lixed character while the number in the other rnolariform teeth 

 is somewhat variable. —E. A. Goldman. 



FOSSIL CROCODILES FROM THE CANAL ZONE. 



The section of Vertebrate Paleontology of the U. S. National Museum 

 has recently received from Mr. D. F. MacDonald, geologist for the 

 Panama Canal Commission, two fossil crocodilians found in the canal 

 excavations. Although fragmentary they are of interest as being the 

 first fossil reptilian remains reported from this region. One specimen is 

 from the Culebra formation, opposite Culefera, the other from the Gatun 

 formation, Gatun Locks. Both represent crocodiles of robust propor- 

 tions. — C. IF. Gilmore. 



♦Bull. Amer. Mus. Nat. Hist., XII, pp. 257-1264. 



+ Hist. Nat. Mainm., VI, livr. LX, pi. (Cercomys du Bivsil) with 2 pp. text. Sept. 

 1829. 



X Nouv. Ann. Mus. Hist. Nat., Paris, I, 1832, pp. 449-452, pis. is tiff. 1, 19 tigs. 1-2. 

 « Proc. Zool. Soc. Lond., 1870, p. 749. 



