222 Miller — Three. New Shrews of the Genus Cryptotis. 



C. mexicana, the unicuspids showing no tendency toward the con- 

 spicuously concave posterior border characteristic of these teeth in 

 C. orophila ; inner tubercle of unicuspids faintly developed, much as in 

 C. mexicana per egrina. Upper cheek-teeth sharing in the general reduc- 

 tion of width characteristic of entire skull, this tendency especially 

 noticeable in the large premolar, the posterior border of which is decidedly 

 shorter than outer bonier, while in C. mexicana and C. orophila they are 

 about equal; emargination of posterior borders slight, essentially as in 

 mexicana and orophila ; hypocnes somewhat better developed than usual ; 

 m 3 with well developed metacone and third commissure. Mandibular 

 teeth less robust than in C. mexicana and C. orophila but with no special 

 peculiarities of form. 



Measurements. — Head and body,* 70; tail,* 35; hind foot, 13.6 ( L2.4); 

 condylobasal length of skull. 18.6 ( L9.4)t; lachrymal breadth, 4.2 (5.0); 

 zygomatic breadth, 5.2 (6.0); distance between zygomatic root and 

 gnathion, 8.2 (8.2); breadth of braincase, 9.0 (10.0); depth of braincase, 

 5.4 (5.4); mandible, 10.4 (11.0); maxillary toothrow (entire), 8.8 (9.0), 

 mandible tooth row (entire), 7.8 (8.2). 



Remarks. — Three very distinct species of Cryptotis are now known to 

 occur in Costa Rica: the medium sized C. orophila on the Volcano of 

 Irazu, C. gracilis in Talamanca, and the small C. nigrescens at San .lose. 

 The last is further distinguished from the two others by the reduced con- 

 dition of the posterior molar both above and below; m 3 with mesostyle, 

 metacone, and their commissures very small and barely differentiated, m 3 

 with posterior V reduced to a loop scarcely more than one-fourth as large 

 as anterior V. 



Cryptotis frontalis sp. nov. 



Type— Adult female (in alcohol) No. 123,429, U. S. National Museum. 

 Collected near the City of Tehauntepec, Mexico, by F. Sumichrast. 



Diagnosis. — Size and general appearance as in C. mexicana mexicana. 

 Skull with more robust rostrum and with braincase unusually deepened 

 posteriorly, and rising anteriorly at a much more conspicuous angle (in this 

 respect noticeably surpassing C. nelsoni); teeth larger than in true 

 mexicana but inner tubercles of upper unicuspids less developed, though 

 retaining distinctly pigmented tips. 



Measurements. — Head and body, 06; tail, 27; hind foot, 12.2 (11.0). 

 Skull: condylobasal length, 19.0(18.6)1; zygomatic breadth, 6.2 (6.0); 

 lachrymal breadth, 5.0 (5.0); breadth of braincase, 10.2 (10.0); depth of 

 braincase, 6.2 (5.6); mandible, 10. (i (10.0); maxillary toothrow, 8.6 

 (8.6); mandibular toothrow, 8.0 (8.0). 



*Approximate ; from skin. 



t Measurements in parenthesis are those of an adult female topotype of C. orophila 

 (No. 116,649) . 



t Measurements in parenthesis are those of an adult female topotype of C. mexicana 

 mexicana. 



