1915.] 



SCALOPUS AQUATICUS MACHRIXOIDES. 



4e5 



SCALOPUS AQUATICUS MACHRINOIDES Jackson. 

 Missouri Valley Mole. 

 (PI. II, fig. 7.) 



Scalopus aquatims machrinoides Jackson, Proc. Biol. Soc. Washington, vol. 27, p. 19, 

 February 2, 1914. 



Type locality. — ^Manhattan, Riley County, Kansas. 



Type spedmen. — No. 169717, U. S. Nat. Mus., Biological Siirvey 

 collection; ^ adult, skin and skull; collected June 1, 1910, by 

 W. E. Berg. 



GeograpJiic range. — West of the Mississippi River, except eastern 

 Iowa, from central Minnesota, southeastern South Dakota, and the 

 eastern border of Nebraska, south through northeastern Kansas to 

 extreme northern Ai-kansas. 



General diameters. — Size large, exceeded only by 8, a, maclirinus; 

 color more grayish than machrinus; skull heavy, angular, smaller 

 than that of machrinus, with a shorter rostrum, and relatively smaller 

 inferior mandibular notch. 



Color. — Winter pelage: Upperparts ranging from bister to clove 

 brown, becoming paler on face and wrists; underparts slightly paler 

 than back, and usually showing more slate color of base of hairs, 

 washed ventrally with, raw umber or mummy brown. Summer pelage: 

 Upperparts light drab, drab, or wood brown, paler on face, nose, and 

 ankles; beneath slightly paler than back, more grayish. 



SlcuU. — ^Most nearly hke that of S. a. machrinus but smaller, with 

 a rela.tively shorter rostrum; ascending ramus of mandible not so 

 heavy as in maclirinus, and inferior mandibular notch smaller; 

 rostrum short and broad; molariform dentition very heavy. 



Measurements. — Avera,ge of 3 adult males from Elk River, Minn. : 

 Total length, 172 (168-178); tail vertebrae, 30 (27-32); hhid foot, 

 22.2 (22-22.5). Average of 3 adult females from Fort Leavenworth, 

 Kans., Bismarck, Mo., and Council Bluffs, Iowa: 181 (180-182): 32 

 (31-33); 22.3 (22-23). SluU: Average of 3 skulls of adult males from 

 typelocahty: Greatest length, 37.1 (36.2-37.7); palatilar length, 15.3 

 (15.2-15.5); mastoidal breadth, 19.4 (19.3-19.5); mterorbital breadth, 

 8 (7.9-8.1); maxillary tooth row, 12 (11.8-12.1); mandibular molar- 

 premolar row, 11.8 (11.5-12). 



Remarhs. — The Mississippi River separates the range of S. a. 

 w.acJinnm from that of S. a. macJirinoides except for a short distance 

 where the former extends into Iowa. Specimens from St. Louis, Mo., 

 are somewhat intermediate between the two forms, being larger than 

 typical macJirinoides and having relatively longer rostra. Toward 

 the north (Elk River, Mhm.)^ macJirinoides decreases slightly m size; 

 along the western border of its range it intergrades with S. a. caryi, 



