1893.] ox MAMMALS TIIOM BRITISH CBKTItAL Al'ElCA. 723 



and closes more or less in air, because the correction for the 

 astigmatism is evidently made for air and not for water. Now our 

 iris dilates when the accommodation is relaxed, and contracts when 

 it is called into play ; and if in the Seal the accommodating 

 mechanism be the same as ours, the above-mentioned changes 

 would obviously only make matters worse. 



But here again the question is beset with difEculties, for this 

 myopia could only be of service if it were due to the lens, since any 

 curvatures of the cornea would be neutralized by the water. 



At present my observations go to prove that the iris is to some 

 extent at least under the control of the animal's will, since in one 

 Seal, at any rate, I observed the pupil moving out of all proportion 

 to the accommodation, while, on the other hand, I induced accom- 

 modation by approaching a piece of fish without any alteration in 

 the pupil. 



I hope in a future paper to be able to give some explanation for 

 this extraordinary amount of astigmatism, and although I have a 

 theory I would rather reserve any further attempts at an explanation 

 until I have verified all the facts which bear on the question and 

 examined all objections which can be urged against it. 



4. On some Specimens of Mammals from Lake Mweru, 

 British Central Africa, transmitted by Vice-Consul 

 Alfred Sharpe. By P. L. Sclater, M.A., Ph.D., F.R.S ., 

 Secretary to the Society. 



[Eeceived November 16, 1893.] 



Mr. Alfred Sharpe, H.B.M. Yice-Consul in Southern Nyasaland, 

 has kindly sent me some specimens of the larger Mammals which 

 he obtained during his recent journey from the north end of Lake 

 Nyasa to Lake Mweru and the Luapula ', together with a number 

 of flat native skins procured from the natives at Mweru. These 

 I have now the pleasure of exhibiting. 



In a letter written from Blantyre (28th March, 1893) after his 

 return, Mr. Sharpe gives the following interesting account of the 

 animals met with on his route : — 



" On the road from Nyasa to Tanganyika almost no game is seen 

 until the Saisi is reached [this river, rising in the Mambwe 

 Country, flows N.E. and E. to Lake Hikwa]. There, for the first 

 time on this route from the sea to Tanganyika, one finds the 

 Cobus vardoni, also the Impala {^pyceros melampus), Eoan Ante- 

 lope {Uippotragus equinus), Lichtenstein's Hartebeest {Buhalis 

 UcJitensteini), Eland, Zebra, &c. After leaving the Saisi flats little 

 game is seen on the road thence to the south end of Tanganyika. 



" I doubt if game can, anywhere in Central Africa, be more 



1 See Mr. Sliarpe's paper on this subject, Geogr. Journ. i. p. 524(1893), and 

 the accompanying map. 



