96 



I^OETH AMERICAN FAUITA. 



[No. 38. 



mastoidal breadth, 10.3 (10.1-10.5); interorbital breadth, 5.3 

 (5.2-5.4); maxillary tooth row, 7.1 (7-7.2); mandibular molar- 

 premolar row, 7.3 (7.1-7.5). Average of 6 skulls of adult females 

 from Sumas, British Columbia: Greatest length, 22.4 (21.5-23); 

 palatilar length, 9.4 (9.2-9.5); mastoidal breadth, 10.2 (9.6-10.5); 

 interorbital breadth, 5.3 (5.1-5.5); maxillary tooth row, 7.1 (6.9-7.2); 

 mandibular molar-premolar row, 7.2 (7-7.3). Average of 2 skulls 

 of males from Carberry Ranch (type locality of major), Shasta County, 

 CaL: Greatest length, 22.7 (22.4-23); palatilar length, 9.3 (9.3-9.3); 

 mastoidal breadth, 10.6 (10.5-10.7); interorbital breadth, 5.4 (5.4-5.4); 

 maxillary tooth row, 7 (6.9-7); mandibular molar-premolar row, 7 

 (6.9-7.1). 



Remarks. — This little mole, the most slirewlike of the American 

 members of the family, shows comparatively little geographic varia- 

 tion throughout its rather extensive range; in fact, the local almost 

 obscures the geographic variation. Southward a tendency appears 

 toward an increase in size and toward the development of a 

 cusplike process upon the anterior portion of the cingulum of the 

 second upper premolar; this reaches the climax in N. g. Jiyacinthinus. 

 The presence of this cusplike process on the second upper premolar, 

 however, is not strictly diagnostic since it occasionally crops out, 

 slightly developed, in specimens taken near the northern limit of the 

 range of N. g. gihhsii, or may be absent in specimens of Jiyacinthinus 

 taken near the southern border of its range. Thus, it occurs, weakly 

 developed, in a few specimens from Sumas, British Columbia; it is 

 absent in two specimens from Crescent City, CaL, but is present in 

 five young adults from Eureka, CaL, and in one from Goldbeach, 

 Oreg,; some specimens of TiyaeintJiinus from Cuddeback and Aptos, 

 Cal., have the process, while others lack it. 



The form Neurotrichus gihhsi major Merriam ^ is here placed in 

 synonymy under N. g. gihhsii. The type of major was collected at 

 Carberry Ranch, altitude 4100 feet, between Mount Shasta and 

 Mount Lassen, Shasta County, CaL; a careful comparison of the type, 

 topotypes, and other specimens from the Shasta region, with a large 

 number of specimens from Washington and British Columbia fails to 

 show any differences between major and gihhsii worthy of subspecific 

 recognition; specimens of major average very slightly larger than 

 gihhsii and in some other respects appear to be intermediate in 

 characters between gihhsii and TiyaeintJiinus, but in size and general 

 proportions of skull they are much nearer gihhsii. The presence of 

 an anterior '^cusp^' on the cingulum of the second upper premolar in 

 major is not of diagnostic value, as has been shown in the preceding 



1 Merriam, C. Hart, N, Am. Fauna No. 16, p. 88, 1899. 



