52 



MR. R. I. POCOCK ON THE EXTERNAL 



Rodentia. These cranial features distinguish Chiromys from all 

 Lemurs ; and when taken in conjunction with the teeth, with the 

 paculiarities of the hands and feet, and of the sublingua, they out- 

 weigh, in my opinion, the known differences between the true 

 Mascarene Lemurs (Lemuridae and Indrisidaa) and the Asiatic 

 and African Galagos, Pottos, and Lorises. 



3. With regard to the Galagos, Pottos, and Lorises, I am only 

 acquainted with one invariable cranial character distinguishing 

 them from the Lemuridse and Jndrisidse. This was pointed out 

 by Forsyth Major and has been briefly expressed by Mr. Gregory* 

 as follows : — In the Asiatic forms the ectotympanic is enlarged 

 and external to the bulla of which it forms the outer wall. In 

 the Mascarene forms the ectotympanic is inclosed within the 

 bulla, f prining a ring or horseshoe. To this difference may be 

 added the one pointed out above in connection with the clitoris, 

 which in the Asiatic genera is traversed by the urethra, whereas 

 in the Mascarene forms the urethra opens above the tip of the 

 clitoris. 



In view of these facts, I should divide the Lemuroidea into 

 two series, for which Mr. Gregory's names Lemuriformes for the 

 Lemuridse and Indrisidse, and Lorisiformes for the Lorisidse (or 

 Nycticebida?) and the Galagidae may be adopted. Similarly 

 for the subdivision of the Lemuridse I follow Mr. Gregory in 

 relegating the genera to two subfamilies, the Lemurinae and 

 Chirogaleinae ; but I cannot agree with him that Hapalemur 

 belongs to the Chirogaleina9. That genus appears to me to be 

 essentially a Lemurine, its inclusion in the Chirogaleinse spoiling 

 the definition of the subfamily. 



4, As a matter of minor interest it is quite clear that the 

 genus Lemur as generally admitted and as recognised in this 

 paper is susceptible of division into two or three genera. L. caita, 

 for instance, differs from the other species in having the glands 

 on the fore-limb and the naked heel and scrotum, and also 

 in the structure of the vulva. L. varieyatus is also peculiar in 

 the structure of the vulva. Furthermore, the Galagos of the 

 G. senegalensis-type may be distinguished by the structure of the 

 penis from that of the crass icaudatus -type. Generic names 

 appear to be available for these subdivisions of Lemur and 

 Galago ; but I do not propose to enter into that question now. 



My views above set forth differ in so many particulars from 

 those of Mr. Gregory that it may be interesting to tabulate our 

 classifications side by side, omitting those he adopts based upon 

 extinct genera, which, so far as I am aware, do not materially 

 affect the arrangement of recent forms. 



* Bull. Geol. Soc. Amer. 26, pp. 432-436, 1915. See also Bull. Amer. Mus. Nat.. 

 Hist. 35, pp. 266-267, 1916. 



