On the Duikers referred to Oephalophus maxwelli. 529 



assistance and information as to local conditions, to Dr. G. F. 

 Prior, F.R.S., for assistance in determining salinity, and to 

 other colleagues for identifying sundry forms enumerated 

 above. 



Conclusions. 



(1) Ecologically considered Palwlestrlna ulvce and P. ventrosa 



have distinct areas of distribution, but overlap each 

 other slightly in this area. 



(2) This overlapping is due to the greater adaptability of 



P. ventrosa. 



(3) P. ulvce appears to be delimited by the presence or absence 



of food-plants rather than by chemical or physical 

 causes. 



Works referred to. 



(i) Allen, E. J., and Todd, R. A. Journ. Marine Biol. Assoc. U.K. 

 vi. (n. s.) 1900-02, pp. 151 & 295. 



(2) Cotton, A. D. Roval Comm. Sewage Disposal, 7th Report, App. iv. 



p. 22(1911). 



(3) Johnson, D., and York, IT., Johns Hopkins Univ. Circular, 1912. 



LXI. — Note on the Duikers hitherto referred to Cephalophus 

 maxwelli. By Martin A. C. HiNTON. 



(Published by permission of the Trustees of the British Museum.) 



In determining some duikers collected recently by Mr. 

 Willoughby P. Lowe on two islands in the estuary of the 

 llokelle River, Sierra Leone, I have had occasion to examine 

 all the material in the British Museum hitherto referred to 

 Cephalophus maxwelli. As a result it would appear, firstly, 

 that the mainland specimens in the collection belong to two 

 distinct species, and, secondly, that the island forms are 

 distinct from each other and from those of the mainland. 

 The characters by which the four species recognized in this 

 paper are distinguished may be tabulated as follows : — 



A. Male3 with relatively large horns ; females 

 with horns well developed. Size slightly 

 smaller. 

 a. Nasals normal. 



a . Dorsal pelage not grizzled, uniform 

 dusky ; ears without conspicuous 



