PLATE IX. 



Pecten, Free, except 1. 

 Fig. 



1, P. pusio, Pennant, (Ostrea.) — P., 0., and Hinnites distortus and 



sinuosus. — Brit. co. generally, 15 to 90 fath., C, Irregular, 

 attached to stones, etc. 



2, 3. P. vaeiijs, Linn. {Ostrea.) — P. monotis. — Brit. co. generally, 



3 to 35 fath.; C. Vertically elongate; auricles very unequal. 



4. P. niveus, Macgillivray . — Scotland, R. (15 fath.) Ribs more nu- 



merous than P. varius ; white. 



5, 6, 7. P. opercularis, Linn. (Ostrea.) — 0., and P. submfus, pic- 



tus, lineatus (var. f. 6), and sanguinea. — Brit. co. generally, 5 to 

 100 fath., C. As broad as long ; ribs rounded. 



8. P. Audouinii, Payraudeau. — P. opercularis, var., B. Moll. — Ribs 



angular and squamose. 



9, 10. P. danicus, Chemn. — P. and 0. pes-felis, glaber, triradiata, ad- 



spersus, septemradiata, etc. — Several Scotch localities, 25 to 90 

 fath., Mc. Very variable, extreme vars. f. 9, 10. Auricles more 

 equal than P. tigrinus. 

 11, 12. P. tigrinus, Milller. — P. obsoletus, domesticus, lavis, parvus, 

 etc. — Brit. co. generally, 12 to 60 fath., C. Variable ; one auricle 

 minute, the other large and ribbed. 



13. P. maximus, Linn. (Ostrea.) — P. vulgaris. — Brit. co. generally, 3 



to 40 fath. The common eatable Scallop. Valves unequal. 



14. P. similis, Laskey. — O. and P. tumidus. — Fr. Forth, Isl. Man, 



Lerwick, Cape Clear, etc., Mc. Minute, smooth, with undula- 

 ting marks. 



15. P. striatus, Mutter. — P. aculeatus,fuci, etc. — Scotland, C. ; Eng- 



land, R. 



16. P. furtivus, Loven. — Zetland, Guernsey, etc., 40 to 50 fath., Mr. 



More rounded, and with auricles less broadly based than P. stri- 

 atus. 



Hippothyris, Fixed by byssus. 



17. H. psittacea, Gmel. (Anomia.) — A. rostrum-psittaci, Chem. ; Tere- 



bratula psittacea. — Northumberland, Fr. Forth; deep water, 

 Rr. as Brit. " The Parrot's-beak Anomia." 



Terebratula. Fixed by byssus. 



18. T. cranium, Mutter. — Anomia c., and T. vitrea. — Zetland; deep 



water, unique as Brit. Smooth, oval. 



19. T. capsula, Jeffreys, Ann. Nat. Hist., Jan. 1859. — Belfast Bay, 



R. Minute, punctured. 



