1887] MR. G. E. DOBSON ON THE GENUS MYOSOREX. 575 



4. On the Genus Myosorex, with Description of a new 

 Species from the Rio del Rey (Cameroons) District. 

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



[Eeeeived November 8, 1887.] 



The genus Myosorex^ was founded in 1837 by Dr. J. E, Gray for 

 the reception of a small species of white-toothed Shrew, Sorex 

 varius, Smuts, from the Cape Colony ; which was then at once distin- 

 guished from all other known species of white-toothed Shrews by the 

 short, subequal, and rather coarse hairs covering the tail. Trivial 

 as this character may appear, and as such it has evidently been 

 hitherto regarded by systematic zoologists, it is, however, the only 

 one out of the many enumerated in the original definition of this 

 genus (see footnote below) which is really characteristic of it taken 

 in connection with the white colour of the teeth. 



Myosorex. 



Myosorex, Gray, Proc. Zool. Soc. 1837, p. 124. 



General characters those of Crocidura, but distinguished by the 

 absence of long hairs on the tail, which is clothed with short fur 

 of equal or subequal length, by the shortness of the third upper 

 incisor, and by the absence of a distinct cloaca, the generative organs 

 and the alimentary canal opening on the surface close together by 

 distinct orifices. 



Dentition : ^""'m.LT 'hT^^'t'"' =30 or 32 teeth. 



Mand. b — b or 7 — 7 



Range. Africa south of the Sahara Desert. 



1. Myosorex varius. 



Sorex varius, Smuts, Mamm. Capens. 1832, p. 8. 



Myosorex varius, Gray, Proc. Zool. Soc. 1837, p. 124. 



This, the largest species of the genus, is somewhat larger than 

 Crocidura aranea. The body is clothed with dense fur, pale reddish 

 grey on the surface, passing gradually into ashy beneath, the basal 

 four-fifths of the hairs bluish ; tail clothed thinly with equal-sized 

 reddish-grey hairs forming a small pencil at the tip. The lateral 

 gland is well developed in males, rudimentary or absent in females, 

 and situated close behind the arm. 



The teeth are very peculiar and characteristic. The upper incisors 

 and premolars are provided with prominent basal processes, the third 



' " Myosorex, Gray. Head elongate, ears hid under the soft fur ; tail elon- 

 gate, slender, covered with short, rigid, close-pressed hairs, when old quadran- 

 gular ; feet and toes not ciliated ; teeth white ; cutting-teeth -;, two upper 



central unequally bifid, the second lateral moderate, the third very small, 

 rudimentary, the fourth small but larger than the third ; front lower cutting- 

 teeth elongate, with an entire sharp upper edge ; second and third lateral teeth 

 small, simple, crowded on the base of the front ones." — Gray, P. Z. S. 1837, 

 p. 124. 



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