GASTEKOrODA. 319 



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

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

 uncini ; gizzard with three longitudinal shelly plates. Egg 



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

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

 (Lo\en.) 



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

 Britain, Mediterranean, Corea, Borneo. 



Fossil, 1 species. Eocene — . France. 



Sub-genus. Clielidonura, A. Adams, (HirundelTa, Gray) B. 

 hirundinaria, Quoy, Mauritius. Shell concealed; outer lip 

 produced posteriorly ijito a spur ; columellar border inflected. 

 Animal^ih. enveloping side-lobes; mantle with two appendages 

 behind, like the lateral processes of Hyalaea. 



DoEiDiTJM, Meckel. 



Etymology, diminutive of Doris. 



Synonym, Accra, Cuvier. Eidothea, Eisso. 



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. 



Gastropteron-, 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; cejDhalic 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, 

 /, side-lobps of tlie toot; m, mantle. The shell s, and gizzard <7, are indistinctly seen 

 through the translucent integuments. 



