16 Proceedings of the Biological Society of Washington. 



the hairs. Ventral surface of body and fore limbs soiled whitish, slightly 

 washed with pale brown across the chest. The bases of the hairs, except 

 at the chin, are dnll plumbeous. AVrists and central part of the meta- 

 carpal area are dark like the back, the fingers and edges of the palm 

 white. The hind legs are dusky all around and this color extends to 

 the entire outer part of the hind foot above, but the three inner toes and 

 the metatarsal area corresponding are white. Tail sharply bicolor; dark 

 like the back on its upper side and practically all around at the tip. 

 Below it is pure white, but this area narrows terminally and ends at 

 about a centimeter from the tip. 



Skull. — The skull does not differ appreciably from that of albiharbis 

 though the braincase seems to be a trifle wider. From palustris, as 

 represented by Alberta specimens assumed to be typical, it differs in the 

 much shorter rostrum, though the braincase is equally broad. The 

 appearance of breadth is therefore much more marked in the Nova Scotian 

 animal, though it is only proportionately broader. The teeth are smaller, 

 but seem essentially the same in structure, though the third unicuspid in 

 the specimens at hand appears to be relatively smaller in comparison 

 with the fourth. 



Measurements. — The collector's measurements of the type specimen are: 

 total length 150.5 mm., tail 66.5, hind foot 20, which are essentially the 

 same as for palustris (Merriam gives 155, 65.5, and 19 respectively for the 

 corresponding measurements taken from Richardson's description, and 

 157, 68, and 20 for a specimen from Edmonton, Alberta). A large male 

 from Halifax, N. S., measures 167, 69, 19.5 for these respective dimensions. 



The following cranial measurements are taken from the type skull, with 

 in parentheses the corresponding dimensions of a specimen of palustris 

 from Alberta: greatest length 20.8 (22.1), basal length 18 (19.5), palatal 

 length 9.1 (10.3), upper tooth row 9 (10), greatest width outside molars 

 5.8 (6.1), greatest width of brain case 10.1 (10). For a specimen of 

 palustris from Edmonton, Alberta, Merriam gives, greatest length 22.5, 

 width of braincase 10.2. 



Remarks. — The Nova Scotia Water Shrew is closely related to N. palustris 

 palustris, from which it differs in the size and proportions of the skull, 

 and in its slightly browner color, which on the belly is sometimes a very 

 pronounced wash. Intergradation takes place, probably in the region of 

 southern Canada. Preble (No. Amer. Fauna, 1902, No. 22, p. 71) con- 

 siders specimens from the north of Lake Winnipeg as representing/)aZu8<m, 

 with which their skulls agree ; he mentions, however, that in some speci- 

 mens the belly is slightly washed with brownish. Probably the smaller 

 Rocky Mountain Water Shrew (navigator) should likewise be considered 

 a subspecies of palustris and it was so regarded by Merriam (No. Amer. 

 Fauna, 1895, No. 10, p. 93) who says that it " fluctuates considerably in 

 size in the various mountain ranges it inhabits, and seems to intergrade 

 completely with S. palustris. Specimens from the Bighorn and Wind 

 River mountains in Wyoming are fairly intermediate, and it is probable 

 that intergrades will be found along the east base of the Rocky Mountains 

 in Alberta." The White-lipped Water Shrew (N. albibarbis) the type 



