GASTEEOPODA. 319 



olblong ; eyeless ; foot broad ; lateral lobes large, but not 

 enveloping ; tongue with, two or four series of sickle-shaped 

 nncini; gizzard with three longitudinal shelly plates. Egg 



Fig. 138. Philme aperta.* 



capsules ovate, in single series on a long spiral thread; fry 

 with a ciliated head-veil and an operculated, spiral shell. 

 (Loven.) 



JDistribution, 16 species. West Indies, Greenland, Norway, 

 Britain, Mediterranean, Corea, Borneo. 



Fossil, 7 species. Eocene — . France. 



Siib-genus. Chelidonura, A. Adams, (Hirundella, Gray) B. 

 birundinaria, Q,uoy, Mauritius. Shell concealed; outer lip 

 produced posteriorly into a spur ; columellar border inflected. 

 Animal with enveloping side-lobes ; mantle with two appendages 

 behind, like the lateral processes of Hyalaea. 



DoRiDiUM, Meckel. 



Etymology, diminutive of Doris. 



Synonym, Acera, Cuvier. Eidothea, E-isso. 



Type, D. membranaceum, Meek. Mediterranean. 



Distribution, 3 species. South Europe. 



Animal oblong, truncated behind, the angles produced and 

 dilated or filiform ; head ovate-oblong, retuse in front ; side- 

 lobes expanded, wing-like; mantle investing a rudimentary, 

 membranous shell. 



GASTEOPTEEOisr, Meckel. 



Type, G. Meckelii, Bl. (Clio amate, Chiaje) Mediterranean. 



Animal shell-less, oval, with side-lobes developed into wing- 

 like expansions, meeting and uniting behind; cephalic disk 

 triangular, obtuse in front, pointed behind, eyes centrally 

 immersed; lingual teeth 5.1.5; mantle? branchial plume 

 exposed on the right side ; reproductive orifice in front of the 



* From a specimen dredged at Folkestone ; o, mouth ; c, head, or cephalic disc, 

 I, side-lobes of the foot; m, mantle. The sheU s, and gizzard^, are indistinctly seen 

 through tlie translucent integuments. 



