DIMYAIRA. 143 



Myatella striata.— The Striated Myatella. Plate XV I. 

 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 crenulated. One-eighth of 

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



Genus 63.— SPENIA.— r«?ton. 



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

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

 tened. 



Spenia Binghami — Bingham's Spenia, Plate XVIII. fig. 

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

 convex, and incurved at the extremity, and envelopes the smaller 

 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. 



Genus G\.—GhY CIM.¥>RIS.— Lamarck. 



Generic Character • — Transverse, gaping widely at each extre- 

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

 These shells aie distinguished from the Solen by having- teeth at the liing-p. 



