Vol. 4] Sinclair. — Mammalia from Quaternary Caves. 147 



Measurements. 



Length of rostrum from base of I" to anterior surface of 



incisor 13.5mm 



Length of rostrum from postero-inf erior extremity of pre- 



maxillae to anterior surface of incisor 10.5 



Greatest width of rostrum 7.5 



Depth of rostrum from posterior extremity of nasals to margin 



of alveolus of P 4 11 



Depth of rostrum from posterior extremity of nasals to postero- 



inferior extremity of premaxillae 9 



Width across frontal between orbits 6.5 



P 4 , antero-posterior diameter 1.6 



P 4 . transverse diameter at widest part 1.5 



M 1 , antero posterior diameter 1 



M 1 , transverse diameter 2 



Width of incisor 2 



APLODONTIA MAJOR FOSSILIS, n. Sllb-Sp. 

 PI. 19, Figs. 8 and 9. 



Type. — No. 4160, Univ. of Cal. Palac. Coll. The right mandibular 



ramus, lacking the coronoid process and part of the angle. 

 Cotype.—'No. 5265, Univ. of Cal. Palae. Coll. An imperfect cranium. 

 Locality. — Potter Creek Cave, Shasta Co., California. 



Numerous lower jaws of an Aplodontia were found in all 

 parts of the cave and at various depths beneath the surface of 

 the cave deposit. The jaws all show the characters possessed by 

 the type specimen. They differ from the typical Aplodontia 

 major in having the dental foramen generally wider trans- 

 versely. The ridge in front and below the masseteric fossa, in 

 the fossil form, is usually continued across the lower side of 

 the ramus and connected with the inner prominence of the 

 angle, while in A. major a smooth space exists between the 

 angle and the ridge in front of the masseteric, fossa. In the 

 fossil form the Avail in front of the fossa, above the angle, on 

 the inner side of the ramus, is vertical for a longer distance 

 below the opening of the alveolar canal than in the recent 

 major. So far as it is possible to compare its dimensions with 

 the measurements tabulated by Dr. C. H. Merriam,* the 

 cranium agrees closely with Aplodontia major. 



*Annals N. Y. Acad, of Sciences, Vol. Ill, No. 10, Table facing 

 page 328. 



