98 



NORTH AMERIGAISr FAUNA. 



[No. 3S-. 



distinctly overcast with hoary, due to whitish tips of the longer hair \ 

 worn pelage paler and more brownish; purplish and greenish irides- 

 cence shows in fresh specimens, as in gihhsii. 



SkuU. — Similar to that of N. g. gihhsii but larger (greatest length 

 usually over 23.5 mm.) and relatively wider through braincase, 

 interorbitally, and through rostrum; mastoid region usually heavier 

 and more angular than in gihhsii; anterior portion of cingulum of 

 second upper premolar usually developed into a superior cusplik© 

 process. 



Measuremmis. — ^Average of 6 males from Aptos, Santa Cruz 

 County, Gal.: Total length, 121.5 (118-126); tail vertebrae, 38.3 

 (37-39); hind foot, 16.9 (16.5-17), Shull: Young adult male from 

 type locality: Greatest length, 24.2; palatilar length, 9.8; mastoidal 

 breadth, 11; interorbital breadth, 5.7; maxillary tooth row, 7.4; 

 mandibular molar-premolar row, 7.3. Skull of young adult female 

 from type locality: Greatest length, 23.5; palatilar length, 9.6; 

 mastoidal breadth, 10.6; interorbital breadth, 5.4; maxillary tooth 

 row, 7.3; mandibular molar-premolar row, 7.3. Average of 6 skulls 

 of males from Aptos, Santa Cruz County, Cal.: Greatest length, 

 23.8 (23-24); palatilar length, 9.9 (9.6-10); mastoidal breadth, 10.9 

 (10.7-11.1); interorbital breadth, 5.6 (5.5-5.7); maxillary tooth row 

 7.6 (7.4-7.8) ; mandibular molar-premolar row, 7.6 (7.5-7.7). 



Eemarks, — ^The southern-coast form of Gibbs's mole, N. g. Jiyadn- 

 thinuSj differs from the typical northern form, N. g. gihhsii, chiefly 

 in its larger size and darker color, though frequently specimens 

 are no darker than typical gihhsii. Specimens from the south of San 

 Francisco Bay are not quite so intensely colored as those from the 

 type region, and, on the average, seem to have slightly shorter 

 rostra, but the dUfferences are too trivial for subspecific designation. 



Specimens exarrdned. — ^Total number, 58, as follows: 



California: Aptos, 10; Burlingame, 1; Cazadero, 1;^ Cuddeback, 7;^ Fairfax, 1;^ 

 Freestone, 1;* Fremont Peak, 1; Gualala, 9; Guemeville, 3;^ Inverness, 4;^ 

 Mendocino, l;'^ Nicasio (type locality), 6; Palo Alto, 1;^ Point Arena, 4;* 

 San Greronimo, 1;^ Santa Cruz, 7. 



PLATE I. 

 [Natural size.] 



Pig. 1. Early stage in malting process of Scalopus aquaticus aquaticus (Linnaeus); 

 9 adult; Fort Myer, Va., April 15, 1897. (No. 83686, U. S. Nat. Mus.) 



2. Middle stage in molting process of Scalojpus aquaticus aqitaticus (Linnaeus); 



9 adult; Falls Cliurch, Va., May 26, 1907. (No. 144453, U. S. Nat. Mus.) 



3. NestUng young of Scalopus aquaticus howelli Jackson; Jackson, N. C. (No, 



7250, U. S. Nat. Mus.) 



1 Collection Mtw. Vert. Zool., Univ. California. 



« CoUection Field Mus. Nat. Hist. 



