596 MR. F. E. BEDDARD ON THE [DcC. C, 



An account of the anatomy of Clavularia viridis of Quoy and 

 Gaimard is also given. 

 This paper will be printed entire in the Society's ' Transactions.' 



The following papers were read : — 



1. On the Convolutions of the Cerebral Hemisplseres in 

 certain Rodents. By Frank E. Beddard, M.A., F.R.S., 

 Prosector to the Society. 



[Eeceived December 6, 1892.] 



The Rodents are for the most part smooth-brained animals ; there 

 are, however, several exceptions to the universal applicability of this 

 statement, which have been to some extent dealt with by previous 

 writers, including myself. The Rodent brain has not, however, 

 been subjected to that careful study to which the Ungulate and 

 Carnivorous brains have in the hands of Dr. Krueg and Prof. Mivart. 

 The only paper dealing with the Rodent brain in general known to me 

 is by Dareste (1) ; but this article does not include a full description of 

 the convolutions in any type except in the Capybara, though incidental 

 references are made to other types in the author's general survey of 

 the characters of the cerebral hemispheres in the group. Having 

 formed a collection of Rodents' brains during the last year or two 

 from material that came to hand at the Society's Gardens, I think 

 it will perhaps be worth while to again call the attention of anato- 

 mists and systematists to the structure of the cerebral convolutions 

 in this group of Mammaha. I have examined specimens of the 

 following species, the brains of which show, at any rate, traces of 

 convolutions : — 



Ccelogenys paca. 



Dasyprocta azarce. 



Lagostomus trichodactyhis. 



Capromys pilorides. 



Hydrochcerus capybara. 



Hy stria; crista ta. 



Sphingurus prekensilis. 



villosus. 



Castor canadensis. 



Cavia porcellus. 



Octodon cummingi. 



Myopotamus coypu. 



Lepus cuniculus. 



Aulacodus swindernianus. 



Dolichotis patachonica. 



The last two I have lately described in papers dealing with the 

 general anatomy of the Rodents in question (3, 4). Several of 

 these animals have been studied by previous observers ; I shall 

 refer to them in the following descriptive part of the present paper. 



