234 ONCHIDIID.E. 



Genus ONCHIDELLA, Gray. 



Eye-peduncles short ; buccal appendages lobate. Mantle 

 smooth or granular, without tufts or radiating processes on 

 the dorsal surface. 



Ex. 0. granulosa, Lesson, pi. 81, fig. 2, 2, a. 



The species of this genus live on aquatic plants in 

 ditches and damp places. The absence of tufts on the back 

 of the mantle will distinguish them from Peronia, and the 

 lobate buccal appendages and simple mantle from Onchi- 

 dium proper. 



Species of Oncliidella. 



acinosa, Gould. marmorata, Less. 



cinerea, Quoy and Gaim. nana, Phil. 



corpulenta, Gould. nigra, Less. 



granulosa, Less. nigricans, Quoy and Gaim. 



Hardwickii, Gray. patelloidea, Quoy and Gaim. 



incisa, Quoy and Gaim. Eeevesii, Gray. 



irrorata, Gould. 



Genus PERONIA, Blainville. 



Eye-peduncles short ; buccal appendages lobate. Mantle 

 with arbusculiform tufts and tubercles on the dorsal surface. 



Syn. Onchidium, Cuv., not Buchan. Onchis, Ferus. 

 Oncus, Agass. Oncis, Herrm. 



Ex. P. Tongana, Quoy and Gaimard, pi. 81, fig. 3. 



The animals of this group are littoral in their habits, 

 living among the stones on beaches above high- water mark, 

 and a little beyond the influence of the tide. They are 

 principally known from the other genera of the family by 



