Mr. G. S. Brady on Cyprideis torosa. 



63 



The following table indicates the Crustacea with which C. to- 

 rosa was found associated in the localities above specified : — 



The animal of C. torosa differs only very slightly from that of 

 the genus Cy there. The limbs (except the first pair of legs, of 

 which, owing to their minute size, I have not been able to obtain a 

 satisfactory drawing) are represented in PI. IV. figs. 11-15. The 

 only characters by which I can distinguish them from the limbs 

 of Cythere are the absence, from the second joint of the inferior 

 antenna, of the long stout seta which is always found in that 

 genus, and the presence, on the coxse of the last pair of legs, of 

 four or five rows of long hairs having apparently a semiverticillate 

 arrangement. The tufts of bristles which occur in other situa- 

 tions are similar in disposition to those of Cythere. Some of the 

 longer setae or hairs are terminated with a peculiar ringed and 

 serrated armature, which is shown at fig. 15. This character is 

 always confined to certain hairs, which are constant in position, 

 and is found likewise in Cythere. I have not been able, in my 

 recent specimens of C. torosa, to detect the regular tuberculation 

 figured and described by Mr. Jones : but there is much difi^erence 

 in the various specimens, according to age and locality ; and it is 

 evident that considerable latitude must be allowed in this as well 

 as in the spinous armature of the carapace. In comparatively 

 few of the Gravesend specimens have I found any appearance of 

 the single spine, while in those from Warkworth it is almost 

 constant. I have frequently, in examining C. torosa, found the 

 carapace almost filled posteriorly with a very large mass of ova. 

 This fully accounts for the prodigious quantities in which the 

 species is found in favourable localities, such as those at Hartle- 

 pool and Warkworth, and is the more remarkable, as in Cythere, 

 so far as I have observed, the ova are veiy few in number. 



Sunderland, Nov. 23, 1863. 



EXPLANATION OF THE PLATES. 

 Plate III. 

 Vig. 1. Cypris oblonga (Brady), dorsal aspect; X 30. 

 Fig. 2. Ditto, ventral aspect ; X 30. 



