SHAW : ON- CYPR^A AND TEIVIA. 313 



In concluding this paper the writer hopes that the notes on the 

 various species of Cyprcea and Trivia will be of some use and interest 

 to those conchologists who make an especial study of this group of 

 molluscs. At first there is sure to be objection to the changing 

 of specific names (in most cases well-known species) which has been 

 suggested, but it is believed, when the reasons for the various 

 changes have been carefully considered, that these alterations will 

 be admitted as justifiable. 



To the following who have kindly helped me in various ways 

 I wish to tender my thanks: — Mr. B. B. "Woodward, Mr. C. D. 

 Sherborn, Professor G. C. Bourne, Mr. H. G. Farmer, Professor W. H. 

 Dall, the Librarians of the Radcliffe Library, Oxford, Marquis de 

 Monterosato, and Mr. R. Bullen iSewton. My especial thanks are 

 due to Mr. E. A. Smith for the trouble he has taken in working 

 out various points with me, and for his kindness in allowing me 

 to examine the types and other specimens of Cypraa and Trivia 

 in the British Museum. 



EXPLANATIOX OF PLATES XII, XIII. 

 Plate XII. 



Fig. 1. Cyprma tiffris. (By H. G. Farmer.) Sub-intestinal and visceral ganglia 

 somewhat reduced, and pedal ganglion slightly enlarged, a. osphradiura ; 

 h. ctenidium ; c. proboscis sac ; d. tentacle ; e. radula ; /. pedal 

 ganglion; (7. sub-intestinal ganglion; /«. right pedal cord; i. gonopore ; 

 j. anus ; k. recto-genital mass ; I. mucous gland ; m. visceral ganglion ; 

 n. renal pore. 



Fig. 2. Trivia, urctica. (By H. 0. N. Shaw.) Pedal ganglia, showing some of 

 the nerves given off. The lines 1-7 indicate the transverse sections so 

 numbered on PL XIII. 



Fig. 3. Pedal ganglia of Cyprmi arabica (after Bouvier). 



Plate XIII. 



Figs. 1-7. Transverse sections of the pedal ganglia of Trivia arcfica, as shown by 

 the lines in Fig. 2 on Pl. XII. (By H. 0. jST. Shaw.) 



