LiMxorniLA. 235 



the arbusculiform aud other appendages of the mantle, 



which have sometimes been mistaken for gills. One species 

 is found on the coasts of Britain. 



Species of Peronia. 



Celtica, Cuv. Parthenopeia, Chiaje. 



femigiuea, Less. Peronii, Savigny. 



indolens, Couth. punctata, Qitoy and Gaim. 



marginata, Couth. Tougana, Quoy and Gaim. 

 Mauritiaua, Blainv. 



Genus BUCHANANIA, Lesson. 



Eye-peduncles short and tapering at their ends ; oral 

 appendages simple, subulate. Mantle smooth, with a large 

 central tubercle and radiating striae. Foot ovate, small. 

 Vent ? posterior, dorsal. 



Ex. B. onchidioides, Lesson, pi. 81, fig. 4, 4, a. 



This somewhat doubtful genus is founded upon a curious 

 limaciform animal from the coast of Chili, and figured by 

 M. Lesson in the Zoology of the Voyage of the Coquille. 

 In most particulars it seems to resemble Onchidium } but the 

 vent is dorsal as in Onchidoris, and the back of the 

 mantle is smooth, with striae radiating from a single central 

 tubercle. 



Sub-order LIMNOPHILA. 



Tentacles sub-cylindrical or flattened, simply contractile ; 

 eyes sessile. 

 Animal lacustrine or fluviatile. 



