426 Rev. L. Jenyns on the British Shrews. 



Sp. 4. & ciliatus, Sow. {Ciliated Shrew.) Black above, 

 greyish black beneath ; throat yellowish ash : feet and tail 

 strongly ciliated with greyish hairs. 



S. ciliatus, Sow. Brit. Misc. pi. 49. — S. remifer, Yarr. in Loud. Mag. Nat. 



Hist. v. p. 598. Man. Brit. Vert. p. 18.— Oared shrew, Bell. Brit. 



Quad. p. 1 1 9. 

 Uab. Found in the same situations as the preceding. 



Note. — Before concluding it may be well to apprise those 

 naturalists who may be led by Duvernoy^s memoirs, or by 

 either of my own, to examine the dentition of our native shrews, 

 that attention must be paid to the age of the individual before 

 determining the true characters of the teeth in any species. 

 It is only in adult middle-aged specimens that they can be 

 safely trusted. In the young always, and occasionally in the 

 very old, the teeth have an ambiguous appearance, which might 

 easily mislead a hasty observer. In the instance of the former, 

 this ambiguity arises from the circumstance of the teeth not 

 showing themselves at first, but being covered over with the 

 periosteum, which is common to them and the bone in which 

 they are implanted*, and which is not thrown off till after the 

 individual has considerably advanced in growth, and so far 

 assumed all its other characters as to appear mature. Also 

 this skin is not cast off all at once, but will be found still 

 investing the smaller teeth after that the larger and more 

 pointed ones are protruded. In a specimen of the S. tetra- 

 gonurus, which measured 2 inches 2 lines in length, ex- 

 clusive of the tail, and which, until the teeth had been exa- 

 mined more closely, was never suspected to be immature, the 

 molars and the middle incisors were found prominent, whilst 

 all the lateral incisors were still concealed by the periosteum, 

 so as to present the appearance of one continuous bone or 

 tooth, with a sharp edge, filling the entire space between the 



* There are some peculiarities connected with the first formation of the 

 teeth in the shrews, for the details of which I must refer the reader to 

 Duvernoy's first memoir on these animals. I shall simply observe here, 

 that the teeth do not receive their first development within the osseous por- 

 tion of the jaw to be afterwards gradually evolved, as in the case of other 

 Mammalia, but are found from the period of birth in the exact places 

 they are to occupy in after-life, being simply enveloped by the periosteum 

 of the bone to which they are attached. From this and other circumstances, 

 Duvernoy infers that in these animals there are no milk-teeth to be suc- 

 ceeded by a second set at the season of maturity. 



