PALiEONTOLOGICAL APPENDIX— EXTINCT HODENTI A. 947 



ARVICOLA (ISODELTA) SPEOTHEN Cope. 



Anicola tpeothen Copk, Proc. Amer. Pbll. 8oc. Philn. 1871, 87, Bg. 13. 



Described from " the entire dentition of the left ramus mandibali, with a few frag- 

 ments of the iu\jacent bone", from the Port Kennedy bone-cave, Fenusylvauin. 

 Anterior lower molar with one less triangle " than in any species of the section Ami- 

 cola ", and hence reg'\rded as representing a new subgenerip type. 



ARVICOLA (PITYMYS) TETKADELTA Cope. , 



Jraioola Mr<ul(i;<a Cope, Proo. Amer. Phil. 8oc. Pliila. 1871, 8j, Ak- l*!. ^ •. . . ,, * 



Described from a portion of the skull embracing the second and third upper molars. 

 Differs from the other known North American Arvicola in the form of the enamel loops 

 of the molars. Port Kennedy bone-caves, Pennsylvania. 



AKVICOLA (PITYMV8) DIDELTA Cope. 



JniooU didclta Cope, Proo. Amer. Pliil. Soc. Phila. 1871, 89, fig. Ifi. 



Described from "the mandibular rami of five and the superior dentition of proba- 

 bly three individuals", from the Port Kennedy bone-caves. Allied to Arvicola (Pilymys) 

 pinetornm. ........ 



ARVICOLA INVOLUTA Cope. 



Jrvicola invoJuta Cope, Proc. Amer. PUil. Soc. Phila. 1871, 89, Bg. 18. 



"Established on a nearly complete ramus mandibuli, with the dentition perfectly 

 ))reserved", from .the Port Kennedy bone-caves. It is said to be " nearly allied to the 

 A. pinetorvm, differing principally in the form of the anterior lower molar". About the 

 size of A. riparitts. 



ARVICOLA 8IGMODU8 Cope. 



/trvicola ligmodm CoPK, Proo. Amor. Phil. Soo. Phila. 1871, 90, fig. 17. 



Based on "three imperfect mandibular rami, two with the dentition complete, the 

 other with the posterior molar only wanting". Aboat the size of A. ripariua. Its 

 ■ baracters are said to be near those of " A. austera, Lee." 



ARVICOLA (ANAPTOGONIA) HIATIDEN8 Copo. 



Arrfoola hiatide«$ Cope, Proo. Amer. Phil. Soc. Phila. 1871, 91, fig. 18. 



Based on sevend molar teeth, which are several times larger than the correspond- 

 ing teeth of any of the above-named species, " and suggest the genus Fiber^. It is sug- 

 gested that it may not be referable to either Arvicola or Fiber, and that it may require 

 to stand as a separate genus. From the Port Kennedy bone-cares, Pennsylvania. 



GEOMYID^. 



0E0MT8 BI8ULCATUS Marth. 



Otomjit hisulcaltit Marsh, Amer. Junru. Sci. and ArU, 3d ser. ii, Ib/l, 131. 



Apparently nearly allied to Oeomys burnariut. From Pliocene strata, near Camp 

 Tborne, Loup Fork, Northern Nebraska. 



