478 Mr. W. Clark on the Classification of the 



interim amongst the Conovuli rather than in this family, as it 

 wants the distinguishing character of the Bullse, the gizzard ; and 

 we believe the Amphisphyra hyalina of Loven, though displaying 

 the form of a Bulla, does not belong to that family, as some au- 

 thors have stated it not to have a gizzard. Bullcea, an undoubted 

 branch of this family, is illustrated copiously in our account of 

 the B. aperta, also by descriptions of B. pruinosa, B. punctata, 

 and B. catena, published many years ago in vol. iii. p. 339 of the 

 'Zoological Magazine.^ ''» .filwaiaqo 



The remainder of the hermaphrodite MoUusca, whether strictly 

 so, or with congression, consist of the land and freshwater tribes, 

 with a very few bisexual Pectinibranchiata, some breathing air, 

 and others water; the former are repi'csented by Cyclostoma, 

 Acme and Carychium, the latter by Paludina, Neritina and Val- 

 vata ; and the strict hermaphrodites by the Cyclades and Unio- 

 nidaj ; the Limaces and Helices represent the hermaphroditism 

 of the second degree. Though it is not my plan to enter on the 

 land and freshwater tribes which have been so well illustrated by 

 Mr. Gray in his ' Manual,' I have considered it would be desi- 

 rable to insert the families and a few of the leading genera, to 

 show their natural position in respect to the other moUuscan 

 groups, and preserve unbroken the chain of the synopsis. The 

 Pulmonifera, springing from TornateHa, commence one of the 

 lateral branches, followed by the Littorinida;. The Conovulidse, 

 also proceeding from Toi-natella and followed by the Pyrami- 

 dellidse, form the second branch, both merging in the main line 

 at Scalaria, the first genus of the newly constituted family of the 

 Peloridse. 



Fifth Division. 



Gastei-opoda pectinibranchiata . 



Bisexual. 



The Littorinidse are so fully mentioned as to require no par- 

 ticular observations. A peculiar group of the animals of this di- 

 vision have eyes at the internal bases of the tentacula ; it includes 

 the Conovulidse and Pyramidellidse ; the first has two genera, Co- 

 novulus and Pedipes, and the provisional one of Otina ; the latter 

 comprises .i4cme and CarycAiwrn, land branchifers, and Truncatella, 

 Chemnitzia, Eulima and Aclis : both families are branchiferous, 

 except perhaps the Conovulidse, which may be pulmoniferous and 

 hermaphrodite. We presume Acme and Carychium to be bisexual, 

 but we are not sure of this ; we place them provisionally with the 

 iPyramidellidse. - >u; .4 



Though the Conovulidse may not as yet have received the last 

 seal of certainty as regards their branchial organization, still their 



