MAMMALS—SORICINAE—SOREX HAYDENI. 29 
in the dense fur; head and body about 1} inches long; tail vertebrae 1}; tail considerably 
swollen towards the middle; hind foot 0.40 of an inch ; teeth pitchy chestnut. 
Above, grayish chestnut brown. Beneath, whitish. 
S. personatus.—Size very small; ears large; head under 7-tenths of an inch ; head and body 
under 1} inches; tail vertebrz little over 1 inch; hind feet less than 4-tenths of an inch. 
SOREX HAYDENI, Baird. 
Sp. Cu,—Head less than 8-tenths of an inch ; acutely attenuated. Body about 1.75 hundredths of an inch; vertebrz of tail 
1.25. Tail very thich and swollen ; hind feet 4-tenths of an inch ; teeth pitchy chestnut. 
Color above, grayish chestnut brown ; beneath, whitish ; upper premolar not imbricated ; 3d and 4th equal, and decidedly 
less than the two anterior. 
This very diminutive shrew has the head slender and acutely elongated ; the body very 
slender. The muzzle is naked and quite deeply divided. The eye is rather prominent, its 
centre nearer the anterior base of the concha than the muzzle, showing this to be less elongated 
than in some species of the group. The ear is rather large and open, the concha directed back- 
wards ; the antitragal and helicoid valves large ; naked anteriorly ; full-haired on the edges. In 
fact, the furring of the ear is so full as quite to conceal the concha, and to convey the impression of 
its absence. The tail is about as long as the body, (without head,) or a little longer. It is very 
thin at the base, about the diameter of the tibia; it, however, swells rapidly towards the mid- 
dle, and then tapers gently to the tip. It is round and densely clothed with long hairs con- 
cealing the annuli, and ending in a pencil. 
The feet are small, especially the hinder ones, which are only about 4-tenths of an inch long. 
These are naked below, except at the heel, where they are covered with hairs, except a narrow 
space along the median line, which is, however, concealed by the overhanging bristles. The 
rest of the sole is covered with small tubercles, with six larger ones interspersed. The first claw 
reaches beyond the junction of the second and third ; the second, third, and fourth are nearly 
equal, but progressively longer. The tip of the fifth claw reaches nearly to the base of the 
fourth. The feet are rather broad, and covered with longish lustrous hairs. 
The colors of the shrew are a rather light, but not bright-grayish, chestnut brown above ; 
beneath, lighter yellowish white, with a tinge of brown. The tail is brown above, dusky at the 
tip and beneath, with the feet light gray. The tip of the teeth are pitchy chestnut. 
The skull is slender, but rather short. The teeth are 32 in number. The premolars are 
conical, not overlapping ; the points acute and directed downwards; the two anterior about 
equal to the basal hook of the anterior incisor; the third and fourth equal, but abruptly smaller. 
The last premolar is very small. There is a prominent lobe on the inner side of the anterior 
upper incisors, each in contact with its fellow. 
The lower anterior incisor is rather deep, with prominent lobes on the edge, besides the tip. 
It extends posteriorly to below the middle of the second premolar ; this is distinctly bicuspid, 
the anterior cusp the highest. 
