VERTEBRATE REMAINS, PORT KENNEDY BONE DEPOSIT. 219 



of the surface between it and the anterior border of the crown. This border passes 

 regularly into both the internal and external faces, while the posterior border is 

 continuous with the external face, but joins the internal abruptly. The transverse 

 diameter of the posterior part of the crown is greater than that of the anterior part, 

 which is pinched. The hard dentine layer is much thinner on the internal than the 

 external side of the grinding face. Hence, the former is worn at its middle much 

 more than the latter, producing a chisel-like instrument. 



Measurements. 



mm. 



Length of fragment of tooth ; 50 



Diameter, anteroposterior ; 42 



" transverse anterior ; 10 



" " middle; 11 



" " posterior; 12 



This tooth bears a resemblance to the one described by Leidy as a type of a sepa- 

 rate genus under the name of Ereptodon priscus. 1 If that tooth were a superior 

 tooth and this one an inferior one, they might almost be referred to the same species, 

 but for the fact that in Leidy' s species the hard dentine is said to be as thick on the 

 internal as on the external side of the crown. But I suspect that Leidy' s tooth is 

 from the lower jaw, as is probably the one here described. Megalonyx scalper is of 

 the size of M. jeffersonii Cuv. 



INSECTIVORA. 



BLARINA Gray. 

 Blarina simplicidens Cope. [Type No. 150, Mus. A. N. S.] 



Micromammalia are preserved in the carbonaceous layers of the Port Kennedy 



deposit along with their large and even gigantic relatives. The present species is 



nearly related to the exisiting short-tailed shrew, so characteristic 



of our fauna, but differs from it in certain small but important 



dental peculiarities. 



A left mandibular ramus is all that represents Blarina simpli- 

 cidens. By the aid of the excellent descriptions and figures given 

 by Dr. Merriam 2 of the species of this genus, I am enabled to 

 determine its relation to the known species. It is about the size of 

 Blarina simplicidens. £> brevicauda, and no especial characters can be found to distin- 

 guish it from that species excepting the forms of the first premolar 

 and last true molar. All the molar teeth are present, together with the large 

 incisor, but the small external incisor is missing. The gap that it has left is small 

 but evident. The crown of the first premolar is somewhat worn and has an antero- 

 posteriorly oval section. It does not have the V form as in all the species figured 



1 Extinct sloth tribe of North America ; Smithsonian Contributions to Knowledge, 1855, p. 46. 



2 Revision of the shrews of the genera Blarina and Notiosorex by Dr. C. Hart Merriam, North American 

 Fauna, No. 10, Washington, 1895. 



