1831.] MR. O. THOMAS ON THE INDIAN SPECIES OF MUS. 521 



EXPLANATION OP PLATE XLIX. 



Fig. 1. External female 03-gaus of virgin Ht/ana crocuta, showing the orifice of 

 the urinogenital canal situate upon the extremity of the glans clitoridis, 

 both beiug included within the dngle chamber bounded by the pre- 

 puce. P, prepuce ; U.G, orifice of the urinogenital canal. 



2. External female organs of H. crocuta subsequent to parturition, lateral 



view. The figure shows that theurinogenital canal instead of opening 

 upon the extremity of the glans chtoridis, as in the virgin, opens 

 altogether hclcm that body ; aud moreover that the extremity of the 

 clitoris and the orifice of the canal are contained in two separate 

 chambers included by the prepuce, and separated by the two portions 

 of the frsenum preputii. P, prepuce; 0, clitoris; U.G, orifice of 

 urinogenital canal. 



3. The same, seen from the front. Externally is the prepuce, within 



which are included, in separate chambers, the clitoris above and the 

 orifice of the urinogenital canal below. 



4. Prostate gland of male Hyana crocuta. W, vasa deferentia. 



P, prostate gland. U, urethra. 



3. On the Indian Species of the Genus Mus. By Oldfield 

 Thomas, P.Z.S., British Museum. 

 [Eeceived March 23, 1881.] 

 (Plates L., LI.) 



The following paper is an attempt to clear up the extreme con- 

 fusion which exists with regard to the synonymy of the Indian 

 species of the extensive genus Alus. How great this confusion is 

 will have heen evident to any one who has tried to affix the proper 

 name to any Indian specimen of the genus ; and it is hoped that the 

 present account of the species, being founded almost entirely on the 

 types, will be of use to collectors and others attempting to name an 

 Indian rat or mouse in the future. The chief, and almost only 

 general paper on the subject is one by the late Mr. E. Blyth, en- 

 titled " A Memoir on the Rats and Mice of India." ' This memoir, 

 which consists of a collection of references to all the Indian species, 

 though extremely useful as giving a nearly complete list of all the 

 previous descriptions, yet cannot be said to have added very much to 

 our knowledge of the Indian rats and mice. Dr. Jerdon, in his 

 ' Mammals of India,' accepted Blyth's determinations, and added 

 but little on his own account. JDr. J. Anderson" has recently 

 written a most useful paper on the species of the subgenus Nesokia, 

 ■which will be referred to later on.* 



One of the chief causes of the existing confusion was the fact 

 that Mr. B. H. Hodgson, formerly British Resident at Nepal, having 

 made a most magnificent collection in that country, described, either 

 himself, or through Dr. Horsfieid of the India Museum, a large 

 number of species of this genus in the briefest possible manner ; so 



' J. A. S. B. xsxii. p. 327 (1863). 

 ^ J. A. S. P. xlvii. p. 214 (1878). 



Proc. Zool. Soc— 1881, No. XXXIV. 34 



