26 MOLLUSCOUS ANIMALS. 



1.3. Depositus pridie Idus Maias. Here tlie deceased was buried 

 on the day after his death. Thus we find in Gruter, 105-i, 8 — gwaj 

 recessit die Ilercurii hora VIII et deposita die lovis Iduum Maiarum, 

 i. e. she died on Wednesday and was buried on Thursday, See other 

 examples in Corsini, Diss, i, p. 12. In Muratori's, 1959, 9, we have 

 an example of an interval of two days — Defunctus die XVI Kal. April, 

 depositus XIIII Kal, i. e. he died on March 17th, and was buried oq 

 March 19th. 



MOLLUSCOUS ANIMALS. 

 No. 3. 



BY EEV. PROPBSSOB HINCKS, F.L.S. 



The class Gasteropoda next claims our attention. It is considerably 

 the largest in the Molluscous sub-kingdom ; is the best representative 

 of its characteristic structure, and occupies the same position among the 

 Molluscous classes which the whole branch occupies among the greater 

 divisions of the animal kingdom, being therefore the typical class in 

 which the greatest number and variety of forms might reasonably be 

 expected. Many attempts have been made at the proper sub-division 

 of this vast assemblage of animal forms. The history of these is not 

 required in connection with my present plan. So far as I can judge 

 the best orders proposed are those of Cuvier with some combinations 

 and modifications more recently suggested. These then I shall assume 

 as a basis and after explaining their distinctions and discussing their 

 mutual relations, I shall enumerate the families belonging to each order, 

 combining or further sub-dividing as may seem to be required. But 

 I must begin by a few observations on the kind of characters employed 

 and their comparative value. 



Cuvier's orders are founded on the position and structure of the 

 organs for aeration. The 1st he calls Pulmonifera, having lungs in- 

 stead of branchiae, by which he means to express breathing air directly, 

 not through the medium of water. Since, however, these organs are 

 not homologous with the lungs of higher animals, but are strictly so 

 with the branchiae of other mollusks, it is better to adopt DeBlainville's 

 name PulmohrancJiiata. The order is generally admitted to be a natu- 

 ral one. 2. Nudibranchiata: I shall as we proceed venture an opinion 

 on the proper series of these orders. It may be supposed that Cuvier 



