Length from tip of nose to root of tail, 2 3/8 inches. Length of tail, 0 3/4 inches. Length from the upper teeth to tip of nose, 0 3/20 inches. Mr. Peale caught this animal in a pitfall, which he had dug for the purpose of catching a wolf. It is a female. Barton, in his Medical and Physical Journal for 1806, p. 67, says, that, "Sorex minutissimus of Zimmerman, has been discovered in the trans-Mississippi part of the United States, in the country that is watered by the Missouri;"--had he reference to this species? This _sorex minutissimus_, is probably synonymous with S. _exilis_, to which our specimens cannot be referred, whilst the character attributed to that species, of "tail very thick in the middle," is considered essential. 2. _Sorex brevicaudus_, SAY.--Blackish-plumbeous above, beneath rather lighter; teeth, blackish; tail, short, robust. Total length from nose to tip of tail, 4-5/8 inch. Total length of the tail, 1 inch. Total length from the upper teeth to the tip of nose, 0-1/8 inch. _Above_ blackish plumbeous, when viewed from before; silvery plumbeous when viewed from behind; _fur_ dense, rather long; _beneath_ rather paler; _head_ large; _eyes_ very minute; _ears_ white, entirely concealed beneath the fur, aperture very large, with two distinct semisepta, (tragus and antitragus?) which are sparsely hairy at tip; _rostrum_ short, with a slightly impressed, abbreviated line above; _nose_ livid brown, emarginate; _mouth_ margined with whitish and with sparse short hairs; _teeth_ piceous-black at tip; _feet_, white, the second, third, and fourth toes subequal, the first and fifth shorter, the former rather shortest, anterior with but very few hairs, nearly naked; _nails_ nearly as long as the toes; _tail_ with rather sparse hairs, nearly of equal diameter, but slightly thickest in the middle, depressed, and nearly as long as the posterior feet. This specimen, which is a male, closely resembles _S. parvus_, but it is much larger; the head is proportionably much larger and more elongated; the tail more robust, and the inferior anterior pair of incisores are similar to those of S. _constrictus_, fig. 7. pl. 15. of the Mem. du Mus. by Mr. Geoffroy St. Hilaire. The incisors of the superior jaw are twelve in number, in a cranium belonging to this species, five on each side in addition the two larger anterior ones; the posterior tooth of the lateral ones is smallest. May not this be the animal mentioned by the late professor Barton in his Medical and Physical Journal, for March, 1816, which, he says, "may be called the black shrew?" I do not know that the black shrew has ever received any further notice, unless it is the same species to which Mr. Ord has applied the name of _Sorex niger_.--JAMES.