450 



PSEUDOLAMELLIBRANCHIATA 



open, duplicated, folded back, with pallial ocelli ; branchiae not 



concrescent with the mantle ; shell 

 with unequal " ears " at the umbo, 

 hinge-teeth lamelliform, often ob- 

 scure. Silurian . Principal 



genera : Pedum, Qhlamys, Kinnites, 

 Jlemipecten, Amussium, Pecten ; 

 Aviculopecten (Palaeozoic), Creni- 

 pecten. 



Fam. 5. Limidae. — Mantle edge 

 as in Pecten, tentaculate ; shell sub- 

 equivalve, eared, fixed by a byssus 

 or free. Carboniferous . Gen- 

 era: Lima (Fig. 85, p. 179), Limea. 

 Fam. 6. Spondylidae, — Foot 

 with a peduncular appendage, no 



byssus, numerous pallial ocelli; shell fixed by right valve, 



surface often very spinose, two cardinal teeth in each valve. 



Jurassic . GenevO: : Plicatida, Spondylus; Terquemia (\jVd&). 



Fig 



303. — Pecten pallium L. 

 Indies. 



East 



Fig. 304. — Spondylus 

 petroselinum Sowb., 

 Mauritius ; on a coral. 



Fam. 7. Dimyidae. — Shell ostreiform, fixed, hinge with or 

 without symmetrical teeth, two muscular impressions. Single 

 genus, Dimya (Tertiary). 



