74 Monograph on the Cj/prceidece, by Mr. Graj. 



places them aM in that genus, but Bulla differs most essentially 

 from them ; in the animals by the position of their branchiae, and 

 their being half hermaphrodite, and in the shell by the aperture 

 being rouuded and quite entire at each end, and the edges not 

 being thickened, nor the back covered with a shelly coat, for the 

 shell is here covered with the soldered reflected lobes of the 

 mantle ; the connection is most apparent by means of Ovulapatula 

 and Bulla Naucum, in the latter of which there are some slight 

 appearances of a curved canal at each end of the aperture, as in 

 the character of the Cypraeideae, but it has not the enamelled back. 



This family has some analogy in their polished coats, first, to 

 the 3Iarginellee, which induced Montagu to call a species of 

 that genus, Cypraea Voluta ; and indeed such is the affinity be- 

 tween the young of this species, which has been called Bulla 

 dtaphana, that Dillwyn has considered it as the young of 

 C. Europea ; in which Montagu also appears to have coincided, 

 until he observed a totally different construction in the animal ; 

 but I believe that M. persicula is the most analogical species 

 of this genus; and secondly to the Olivce which differ essentially 

 in having an operculum, and all the characters of the Buccinoidew. 



The natural arrangement of this family into sections, I almost 

 despair of, for I have had most of the species lying before me, 

 and have examined them day after day for a fortnight, but have not 

 yet succeeded to my entire satisfaction. I have placed them 

 as well as I can for the present, and shall therefore, if I am 

 fortunate enough to discover a better arrangement, lay it before 

 the public ; doubtless when further discoveries in this extensive 

 genus shall have rendered our knowledge somewhat more per- 

 fect, such an arrangement will be more easily attainable; as we 

 observe in the late discovery of a new species, which unites the 

 costated Cypraeae with the Ovular, by having the smooth young 

 state, and the costated shelly coat of that division ; but differs 

 from them in the want of the thickened, toothed inner lip, which 

 thus supplies the link which was wanting. 



This family is divisable into three genera, thus : 



Cypr-ea. Shell, when young, polished, inner lip thickened, 

 plailcd, outer lip involute plaited. 



