xiii. 
Akeride. 
Akera, Miller, 1776. 
(type) A. bullata, Midd. 
Haminea (Leach), Gray, 1847. 
H. hydatis (L.) 
Our species is now frequently distinguished as H. navicula, Da Costa, 
but sufficient specific distinction is not apparent. 
Philinide. 
Philine, Ascanius, 1772. 
(type) P. aperta, L. 
Our British species will doubtless eventually be broken up into several 
sections, but until some general accord is arrived at, it appears safer to 
use the old name Philine. 
Limacinide. 
Limacina, Cuvier, 1817. 
L. retroversa, Fleming. 
Cavoliniide. 
Clio, L. 
C. pyramidata, L. 
Dr. Pelseneer is followed in the nomenclature, and systematic position 
of the last two families. 
B. ANASPIDEA. 
Aplysiide. 
Aplysia, L., 1767. 
(example) A. punctata, L. 
Strietly speaking Tethys, Z. (1758), ought perhaps to be used for this 
genus. 
C. NOTASPIDEA. 
Pleurobranchide. 
Pleurobranchus, Cuvier, 1805. 
The type is P. Peroni, Cuvier ; sub-genera seem hardly necessary for 
our two species, P. tuberculatus (= membranacens) and P. plumula. 
Luncinide. 
Runcina, Forbes, 1851. 
R. Hancocki, Forbes. 
