1890.] ON THE GENERA OF THE FAMILY SORICID.E. 49 



2. A Synopsis of the Genera of the Family Soricidce. 

 By G. E. DoBsoN, M.A., F.R.S. 



[Received December 21, 1S89.] 



The following synopsis of the genera of the family Soricidce has been 

 based on a very careful examination ot' a great number of specimens 

 representing nearly all the known species, and differs from preceding 

 synopses and classifications not only in the number and mode of 

 arrangement of the genera, but also in many of the characters used 

 for their discrimination \ In such a very compact family it is 

 extremely difficult to obtain characters sufficiently salient to distin- 

 guish the genera when presented in synoptical form, and I am well 

 aware that the discovery of new species may render changes 

 inevitable in the definition of some of tlie genera as given below. 

 While certain species, such as So? ex vulgaris and Blarina brevicauda, 

 are easily relegated to their respective genera, this is not so readily 

 effected with other species in which many of what appear to be 

 the most important generic characters are either feebly developed 

 or are altogether absent. So closely, indeed, are the species allied, 

 all possessing the same number and character of mandibular teeth 

 (Myosorex varius, in which there is a seventh pair of rudimentary 

 lower teeth, can scarcely be considered an exception), that it is pro- 

 bable that the only really natural division of the Shrews is iuto two 

 sections, one including the white-toothed and the other the red- 

 toothed species. 



I. Teeth red-tipped Subfamily SORTCIN.E. 



a. Tail clothed with equal or subequal sized hairs ; glans 

 penis eyiindroid or taperiug. ( Terrestrial, rarely aquatic.) 

 a'. Opening of male or female generative organs separated 

 from the anal orifice. 

 a". Ear-conch well developed ; tail long. 



Dent. i't-"-P'°- •-'-«='■ "'■3-3 ^ 32 teeth Sore.k. 



inand. 6 — b 



' Most of the synopses and classifications of the genera were based upon the 

 dental formulaj of which a resume is given in Brandt's well-known papers on 

 the dentition of the Shrews (Bullet. Soc. Imp. Nat. Moscou, t. xli. 2'^ part, 

 pp. 76-95, 1868, t. xliii. 2*^ part. pp. 1-40, 1871). Since the appearance of 

 Brandt's work A. Milne-Edwards published in 1872 (Recherches pour servir k 

 I'Hist. Nat. des Mannniferes, p. 259) a synopsis of the genera of this family, by 

 far the most noticeable of the classifications which had yet appeared. This 

 classification was adopted by me in the article " Mammalia," Encyclop. Britan- 

 nica, 9th edition, 1882. 



^ Brandt {I. c.) has clearly shown that the position of the premaxillary 

 suture in Sorex vulgaris and in S. minutiis is between the third and fourth 

 unicuspidate teeth, and that therefore there are 4 upper incisors on each 

 side in these species, one more than in any other species of placental 

 mammal not belonging to this family and to be met with among existing 

 mammals in the Marsiipialia only. 



^ As the anterior maxillary tooth is neither functionally nor morphologically 

 a canine in any species of this family, I have not designated it as such in the 

 dental formulae, but have included it in the number of the premolars. 



Proc. Zool. Soc.~1890, No. IV. 4 



