DIMYAIRA. 143 



Myatella striata. — The Striated Myatella. Plate XVI. 

 fig. 12 and 30. Subpellucid, white, of a delicate texture, longi- 

 tudinally striated ; inside white, slightly reflecting a nacred hue. 

 Length, half an inch ; breadth, an inch. Inhabits the sea at 

 Tenby in Wales. 



Genus 62. — CRENELLA — Brown. 



Generic Character. — Oblong-ovate, equilateral, ventricose; 

 beaks obtuse, slightly turned to one side ; hinge without teeth, 

 but with a flattened, slightly crenated plate in each valve ; the 

 right valve with a triangular, horizontal, projecting, reflexed 

 plate, and the left one with an oblique plate, both of which are 

 slightly crenated. 



Crenella elliptica.— The Oval Crenella. Plate XVIII. 

 fig. 13. Ovate, ventricose; with decussated striae; greenish- 

 yellow, inside nacred, the margins crennlated. One-eighth of 

 an inch long. Inhabits the coasts of Zetland and Argyle. 



Genus 63.— SPENI A— JwyYon. 



Generic Character. — Transversely oblong-ovate; slightly tor- 

 tuous ; hinge without teeth, but with the cardinal margin flat- 

 tened, 



Spenia Bingliami — Bingham's Spenia. Plate XV^III. fig. 

 H. Upper valve flat, much smaller than the under, which is 

 convex, and incurved at the extremity, and envelopes thesmaile*- 

 valve ; covered with a reddish-brown epidermis ; inside bluish 

 white. Half an inch broad. Inhabits the Devonshire coast. 



TRIBE II. SOLENIDES. 



Shells transversely elongated, destitute of accessory pieces 

 and gaping at the lateral extremities only ; ligament external. 



Ge?msGi. — GLYCIMERIS.— i:amfl;•c/^ 



Generic Character — Transverse, gaping widely at each extre- 

 mity ; hinge callous, destitute of teeth-, ligament external. 

 These shells are distinguished from the Solen by having teeth at tlie iiinge. 



