458 



MOLLUSCA 



PHYLUM VI 



sculptured, nearly equi valve, with small, unequal ears, and deep byssal notch with well- 

 developed ctenolium. Trias to Recent. 



Camptoncctcs Ag. (Fig. 712). Shell small, thin, nearly smooth, with fine divergent 

 striation radiating from a median line. Jura to Recent. 



Fio. 710. 



Pecten (Chlamys) suhtcxtorius 

 Goldf. Coral-Rag; Nattheim. 



Fig. ril. 



Pcctcn {Chlamys) varius Linn. 

 Pliocene ; Rhodes. 



Fk;. 71-2. 



Pecten (Ento- 



lium) cornutus 



Pecten (Cam2)tonectes) lens Qneniit. Upper 



Sow. Middle Jura ; Balin, Jura ; Hohen- 



near Cracow, i/^. zoUeiu. i/i. 



IhitoUum Meek (Fig. 713). Smooth, thin, witli sub-equal ears diverging at a sharp angle 

 above the beaks ; byssal notch obsolete. Carboniferous to Cretaceous. 



Pseudaiimsium Adams. Shell small, thin, glassy ; the posterior ear obsolete, byssal notch 

 distinct. Cretaceous to Recent. Syncydonema Meek is scarcely different. 



Amusium Bolten (Fig. 714). Shell with raised radial riblets internally; ex- 



Atibu 



Fii;. 714. 

 ii„ u, „i,taUis (Broun). Miocene ; Baden, near Vienna. !/!• 



Fig. 715. 



Hlnnitcs ahjectuK (Pliill.). 

 Middle Jura ; Balin, near 

 Cracow, i/i. 



ternally smootli or delicately sculptured ; valves large, flattisli, with sulj-e(pal ears ; 

 byssal notch inconspicuous or absent. Lias to Eecent. 



Subgenus : Propcamusiuvi Greg. Small, thin, abyssal ; often with relatively conspicuous 

 sculpture, usually discrepant on the valves. Tertiary and Recent. 



Hinnites Defr. (Fig. 715). Shell free and Pectinifurni wlien young, later adherent 

 to other objects and more or less distorted. Trias to Recent. 



Pedum Brug. Shell w^itli an alivincular ligament in an open groove and area like 

 that of Spondylus in the adult ; the young like Chlaviys. Eecent ; sessile on corals. 



Family 34. Spondylidae Fleming. 



Shell inequivalve, nearly equilateral, closed, pecfiniform, obscurely auriculate, mono- 

 myarian; sessile; area am.i)liidetic,inucli larger on the attached valve; ligament alivincular, 

 resiliuvi more or less submerged ; byssus obsolete ; hinge tvith a taxodont provinculum, 



