LUTRARIA. CONCHIFERA. 109 



plish ; colour pale yellow or brownish, with whitish longitudinal 

 rays. 1^ inch long. Inhabits European seas. B. Penn. Brit. 

 Zool. iv. pi. 52, fig. 1. 



M. violacea, Lin. Shell diaphanous, violet, outside finely striated 

 transversely, and the inside longitudinally; anterior slope lan- 

 ceolate, and the posterior oblong. 2|- inches long. Inhabits In- 

 dian seas. Chem. vi. pi. 22, fig. 213, 214. 



M. solida, Lin. Shell subtriangular, thick, opaque, of a yellowish 

 white colour, with a few concentric ridges ; lateral teeth striat- 

 ed ; hinge central. 1^ inch long. Inhabits European seas. B. 

 Penn. Brit. Zool. pi. 55, fig. 2. 



M. subtruncata, Mont. Shell subtriangular, inequilateral, finely 

 striated transversely ; umbones thick and prominent. 7 or 8 

 lines long, and 9 or 10 broad. Inhabits sandy coasts of Britain. 

 B. Browns Illust. pi. 15, fig. 7- 



Gen. 47. LUTRARIA, Lam. Mactra, Lin. 

 Shell inequilateral, transversely oblong or rounded, and gaping 

 at the lateral extremities ; hinge with a tooth as if bent in 

 two, or two teeth, of which one is simple, and an adjoining 

 oblique deltoid hollow, projecting inwards ; no lateral teeth ; 

 ligament interior. 



The Lutrarise are distinguished from the Mactrae by the want of lateral teeth, and 

 by the gape of the shell being in general wider. The animal projects from the an- 

 terior side two syphons, and or, the opposite one a small compressed foot. 



* Shell transversely oblong. 



L. solenoidesy Lam. (Mya oblonga, Gmel.) Shell oblong, with 

 wrinkled transverse striae ; anterior margin prolonged, and the 

 apex rounded j colour dirty white or reddish. 4^ inches broad. 

 Inhabits European seas. B. Brown's Illust. pi. 12, tig. 1. 



L. elliptica, Lam. (M. lutraria, Lin.) Shell oval-oblong, gaping, 

 somewhat pellucid, irregularly striated transversely ; sides rounded, 

 the anterior longest ; colour yellowish white, 4 inches broad. 

 Inhabits European seas. B Browns Illust. pi. 12, fig. 2, 3. 



** Shell orbicular. 



L. compressa, Lam. (Ligvla, Leach.) Shell thin, compressed, of 

 a rounded trigonal form, and transversely striated ; colour dirty 

 gray, sometimes yellowish or reddish. B Browns Illust. pi. 12, 

 fig. 4. 



SECTION IV. CRASSIPEDES. 



Mantle entirely or in part united before ; foot thick, posterior ; 

 shell gaping when shut. 



FAMILY I. MYARIA. 



Ligament interior ; a broad spoon-shaped tooth in each valve, 

 or in one only ; shell gaping at both lateral extremities, or 

 at one only. 



