484 MB. P. L. SCLATEB ON CBKCOPITUECUS GRAYI. [Julie 19, 



on to the pupils without it showing any signs of discomfort, nor 

 did the animal trouble to use its nictitating membranes. La this 

 respect it had the advantage over the big Felidse with pupils which 

 contract in a circular manner, since a circular pupil can never 

 contract completely so long as it remains a circle. 



I obtained precisely the same contraction with a solution of 

 eserine, whilst atropine or cocaine invariably dilated the pupil 

 to its utmost extent, so that under the influence of these two 

 latter alkaloids all pupils became perfectly circular (tig. 2, p. 483). 



In all Mammalia which I have so far examined I have noticed 

 that when atropine is first dropped into the eye a slight con- 

 traction invariably precedes the dilatation. This is most noticeable 

 in the Felidao, as the pupils are so large. In man it may easily be 

 overlooked, owing to the small size of the pupil. 



Suddenly alarming a cat has the effect of momentarily dilating 

 the pupil; whilst 1 have noticed that during sleep the pupil is 

 contracted to an oval, but dilates to its normal condition as soon 

 as the animal wakes. 



In the Wild Cat, the Greneta, and the Civet I found the pupils 

 to be very large and round, but in bright light they contracted to 

 an oval in the same manner as in the domestic cat. In the Lion, 

 Tiger, Puma, and Leopard, in fact in all the large Felidse, the 

 pupil is invariably round, and as a rule retains its circular shape 

 when contracting, thus forming a decided contrast to the smaller 

 Felidae. 



June 19, 1894. 

 Dr. A. Gunthee, F.E.S., Vice-President, in the Chair. 



Mr. Sclater laid on the table the skin of a Monkey of the genus 

 Cercopithecus, which had been deposited in the Society's Gardens 

 by Mr. Wall, of 4 Lansdowne Place, Russell Square, on the 5th 

 of March, 1894, and had died shortly afterwards. He pointed 

 out that this Monkey unquestionably belonged to the local form 

 which he had spoken of in his paper on the Oercopitheci (P. Z. S. 

 1893, p. 255) as Cercopithecus diana Ignitus, and which differed 

 from the ordinary Diana Monkey in its bright chestnut thighs, 

 shorter beard, and other smaller particulars. Mr. Sclater had lately 

 seen a mounted specimen in the Berlin Museum, apparently also 

 referable to this form of C. diana. 



Mr. Sclater also exhibited the typical specimen of Cercopithecus 

 grayi, Fraser, formerly in the Xnowsley Collection, and now 

 belonging to the Free Public and Derby Museum, Liverpool (cf. 

 P. Z. S. 1893, p. 2-56), which had been kindly sent to him for 

 examination by Mr. Henry O. Forbes, Director of that Museum. 

 Mr. Sclater pointed out that there could be no doubt that this 



