Page. 

 10, e. Eight .si<lt- of a proportionally more elevated variety. 

 12, a. Right side of a short, compressed variety, with a part of the Bhell removed to show the 



pallial sinus. 

 I .',/). An opposite side view of a somewhat differently-formed specimen. 

 12, c. Dorsal view of last. 



FlG. 11. NEvERA MoltEAUEXSIS ■ 239 



11, o. Right valve, natural size (type-specimen). 



11, 6. Dorsal view of same. 



11, c. Same valve, magnified, to show more clearly the concentric costaj. 



Flli. 13. CORBULAMEIXA GREGARIA 217 



l:i, «. Left view, showing the unequal sizes of the valves, magnified about four diameters 



(type-specimen). 

 13,6. Anterior view of same, magnified. 

 13, c. Aright-side view, magnified. 



13, d. Hinge and interior of a left valve, magnified so as to show the strongly-projecting lamina 



of the posterior muscular attachment. 



FlG. 14. CORBUI.A CRASSIMARGINATA . .• 244 



1 I.. i. A right-side view, magnified nearly three diameters. 



1 1. b. A ventral \ iew of same, showing the thickened margins (type-specimen). 



14, C. A posterior view of same. 



I'll.. 1">. Callista Deweyi 182 



I"', a. Right side of a specimen with portions of the shell removed, to show the muscular and 



pallial impressions on the internal cast. 

 15,6. Left-side view of a perfect specimen. 



15, c. A dorsal view ot the specimen, represented by lig. 15, n. 

 15, d. Surface-stria', somewhat magnified. 



1">, e. Right side of a larger, somewhat more oval, example. 

 Fig. lti. Tellina? Chevennensis. (See Appendix.) 

 A left-side view of the type-specimen. 



Fig. 17. Pteria ( Pseudoptera) fibrosa 3ti 



17, it. An internal cast of a right valve. (Type of species.) 



17, 6. An outline of the, two valves united, as made out from opposite, detached valves. 



17, c. An imperfect left valve. 



17, d. An imperfect right valve, with somewhat different costai. 



Fig. is. Mactra graciijs 209 



1S,«. Left-side view of type-specimen. 



18, 6. A dorsal view, in outline. 



Fig. 19. Teredo sellu'ormis 262 



19, a. A right-side view, natural size, of type-specimen. 

 19, b. Same, magnified, to show the surface-markings. 



19. c. Internal cast, magnified, to show the deep posterior .sulcus left by an internal ridge. 

 19, d. Burrows, supposed to have been made by this species. 



17 2 



