AVICULIDJE. 93 



aid of winds or insects is almost always necessary to 

 ensure propagation. It is to be hoped that some expe- 

 rienced physiologist will investigate the subject in all 

 its bearings and set at rest this long- agitated question. 



L. hians differs from L. Loscombii in its much larger 

 size, being more depressed, and widely gaping at both 

 sides instead of at the dorsal side only. It is the L. 

 fragilis of Fleming, L. vitrina of Brown, L. aperta of 

 Sowerby, L. inflata of Forbes, and L. tenuis of Leach. 

 The original describer of the species was Schrbter ; but 

 the name he gave it, being in his own language, is not 

 admissible according to scientific rules. The Ostrea 

 tenera of Chemnitz is a West Indian species of Lima and 

 very different from the southern variety of L. hians. 



I found a very small and imperfect single valve of 

 L. inflata (Philippi) in trawl-refuse from the Plymouth 

 coast. It is rather common in the Mediterranean. The 

 shell is tumid and very strong for its size ; the surface 

 is coarsely decussated or reticulate by strong longi- 

 tudinal ribs and transverse plates ; the ears are remark- 

 ably small ; and the hinge is furnished with a horizontal 

 cartilage-pit as in Pecten. Lamarck's species of the 

 same name is distinct from this ; and according to him 

 it inhabits " POcean americain." 



** Mantle open in front, and forming at the posterior side 

 (rarely at both sides) one or two tubes, which are mostly 

 sessile. 



Family IV. AVICU'LID^, Swainson. 



Body obliquely oval or oblong, compressed : mantle open, 

 and free at its edges, which are fringed with cirri : foot small 

 and cylindrical, furnished with a byssal groove. 



