" Baculum^^^ in certain Squirrels. 385 



about one-fourth to oue-sixlli of its length, so that it projects 

 from the sliaft as quite a low cuttino-blade. 



In the more specialized type the lamina is attached to the 

 side of the end of the shaft, and is developed into a long trian- 

 gular and pointed blade, recurved backwards towards the hilt 

 of the shaft, which it may equal or exceed in length. 



A considerable number of species which have been referred 

 to " Scnirus " have bacula of the less specialized compound 

 type, while Lariscus, Tamtops, Dremomys, JVannosciurus, and 

 a further number of " Sciurus " have the more specialized 

 type last described. 



But since the possession of such striking and sharply defin- 

 able characters must indicate blood-relationship, it is evident 

 that forms with all three types of bacula should not be put into 

 the same genus, Sciurus, and I would therefore withdraw 

 from that genus all those with compound bacula, and divide 

 these again into two genera corresponding to the less and 

 the more specialized forms above described. 



Of the first of these, that with the narrow-bladed baculum, 

 the name would appear to be Callosciurus, Gray *, with type 

 *' Sciurus " raffiesii. Other synonymic names are Baginia, 

 Gray t (type S. notatus), Erylhroscinrus, Gray | (ferru- 

 gineus), and Heterosciurus, Trouessart § [ferrugineus). 



The species that I know to be referable to Callosciurus 

 are as follows, the names put in the first column being those 

 of which the character of the baculum has been definitely 

 verified, while the names in brackets indicate a number of 

 prominent species presumed to belong to the genus from 

 their near alliance to the verified species : — 



Callosciurus atrodorsalis .... {rubecnlus.) 



„ caniceps (concolor, griseitnantis, epomophorus.) 



„ castaneoventris . . {gordoni, styani.) 



„ erythrceus {ferrugineus, fiidaysoni. ) 



„ notatus {vittatus, nigrovittatus, saturatus.) 



„ ^:)/«^t> {atncapiUus,caroli,baluensis,erythro- 



melas, prevostii, rcrfflesii, ru/o- 



niger.) 

 „ sladeni {haringtoni.) 



Curiously enough, though there are four names available 

 for the first genus, there are none for the second, that with a 

 long recurved blade on the baculum, and I would therefore 

 propose to give it the name of Tomeutes ||. 



* Ann. & Mag. Nat. Hist. (3) xx. p. 277 (1867). 

 t T. c. p. 279. X T. c. p. 285. 



§ Le Nat. ii. no. 37, p. 292 (1880). 

 II Based on TOjjievs, a shoemaker's knife. 



