OSTREA. 131. 



the margin crenate within : length nearly two inches ; 

 breadth one and a half. 



On the sandy shores of England and Ireland, sometimes 

 fixed to rocks, and sometimes entirely imbedded in hard 

 limestone, v. v. 



6. Ostrea fragilis. Brittle Scallop. 



Lister, pi. \77.f. 14. 



Shell oblong-oral, rather convex, milk-white but not 

 flossy, brittle, semitransparent, with about twenty-five lon- 

 gitudinal and somewhat undulated lines or fine ribs, and 

 two or three minutely finer ones between each of them : 

 valves equal, with the sides unequal, one being straight, 

 the other produced and somewhat angular : hinge a little 

 oblique : beaks pointed, prominent, reaching a little beyond 

 the margin of the hinge, but not meeting together when 

 the valves are closed, in consequence of the thickened in- 

 ner transverse margin, with an oval hollow between them ; 

 ears small, equal, smooth : inside white glossy, striate lon- 

 gitudinally, with the front margin slightly undulated rather 

 than notched : length three-quarters of an inch ; breadth 

 not quite half an inch. 



This is the only British species which has the cartilage 

 placed externally, in the hollow between the beaks, and 

 Hot as in the rest, in an oval internal cavity. 



Devonshire coast : very rare. v. m. 



7. Ostrea subauriculata. Small-eared Scallop. 

 Montagu, pi. 29. f. 2. 



Shell oval-oblong, white, transparent, with numerous 

 longitudinal striae, two of them running down the middle 

 and appearing more conspicuous than the rest from their 

 being opake, and are equally visible on the inside : valves 

 equal, with the sides exactly equal ; the margin slightly 

 crenate : ears very small, equal : hinge exactly in the mid- 

 die, and not sloping to one side as in the last : length a 

 quarter of an inch ; breadth half as much. 



On the Devonshire coast : very rare. v. m. 



8. Ostrea Isevis. Smooth Scallop. 

 Montagu, pl.4.f.4. 



Ostrea similis. Laskcy, Wcry.. Soc. I pi. 8. f. 8. 



Shell 



