I 



I od . 

 1 aid 4 



5 



Kl. t to S. 



PI.ATK XUI 



LrMMMaMA AtfHIMATCM. n. p 



Lateral and cardinal view, nf a large right . n. . f Hie typical form. 



OppnlM view*, i -'. of a lft valvr of the var. tatemeft*) 



The hinge of a right valve of the typical form, x :i. .howlng the rrtral *weep of the teeth 



i-., . 



I -. 



Bnmcwhat weathered rant .if tb InU-rlor. 



Taad i. Lateral and eardlaal view* of a ca*t preaervlng the muacular .car*. 



Fig*. i- U 

 and 10. 

 II aad U. 



U aad 14. 

 Flea. I* aad I 



M>Mi.ijrri< > 

 llnl and lateral view* of lb caul of the Interior up..n which the *pectee waa founded. 



.1 and .-anllnal view* <if a letter piuaiined oa*t, X . *holn tin- muifular war*, palllal lino 

 and Ituprra.!.*!. ..f the hlnfo teeth. 

 Beetoratlon of the Mace. 



117 



MouiotjOPwtt owam. n. *p 



Lateral and cardinal view* of a partial catt of the Interior. 



rifa, IT aad la. 



! 



K .-- .' .. 



Hootofcorejg. OOMI wiua. a. ap . . . . 



Lateral and cardinal view* of aa entire .Iliclaed example of thl. ipecle*. 



MomoLor*i* annul Ulrica ** 



(He* alao plate XXXVL If*. I and S.) 



View of the right aide of the type of thl. tpeetaa. The .pr.-ln.en hi pruaerved chiefly a* a oaat of the 

 Interior and .bow. a* Imprwealoo of the (hallow anterior niuacular .car. 



Ounorwoar* HBUIJUTIK Hall " 



Four vlewa of a rather large peetmen from the toft aide of which the .hell ha* been removed, no a* U> 

 bow the muwular eear* and the lining vertical furrow left by the clavicle. The posterior extrem- 

 ity In thla peclnmn la narrower than usual. 



4. An oblique cardinal view of a oa*t of the Interior. X . .bowing an liupreealon of Ihc ilcnt leu latr.1 lilngn. 

 a. Very perfect ea*tof the Interior (if aa unuiually large right valve, .bowing, he-ldc. the u.ual char- 

 acter*, aaveral obecure ray* on the .Idea and a number of .mall unthonal wan. Minn. Ueol. Hur. 

 MB*. Beg. No. Tat. 



Fig*. 31 to M. OTMODOVTA UMAjn Baiter 



aadtr. Oaatof the Interior of aright valve. Mian. Oeol. Bur. Xua Keg No. Ml*. 

 . Outta-pereha Impreaalon of came. (Bowing the hinge. 



Ftg. a. OrooDOwTA oriroBJita, n. ip "** 



Left aide of a cart of the Interior, .bowing the .trong muecular acan and other character, of the 

 apedea. 



t - a. OlMKWOirTA HACCTA Hall Mt 



A .mall teaUferou* left valve of thl* *pecle* from the middle third of the Trenton .balrm, nrar Cannon 

 Falla. Mlaaeeota. 



Ftca.II to a. OmoDOBTA oonuroama. a. *p *** 



11 aad 8. Two right valve*, the nrt filti the pnaterior amitrlcllon more dl.tlnct than In the other, 

 a. Binge of aright valve. X X. 



Flg*.M to a. OrmKoDoirTA CB*A*CTA. n. *p 



Three view* of a caat of the Interior. 



Fig. IT. OTBBDOHTA OIBBBBULA Baiter f 



(Bee alao text p. too, Ig. 44. f and g) 

 An excellent mold of the Interior of a left valve. 



Fig*, a U> 40. OrnmDOMTA rt-AKOWIUATA L'lrlch 



(Bee alao plate xxxvu. Ig*. SS- ) 

 a. View of the Inner .Ide of a left valve. X *. 

 a. Binge of aame. more highly magniaed. 



40. Artltolaleastof the Interior of a right valve. 



Fig*. 41 to 41. OTUODOWTA CAURATA. n. *p. ... < 



41 and n. A right and left valve, both Imperfect aad varying (llgtly In outline. 



41. Donal view of the left valve. 



Fig*. 44 to t. Or*Ki>iH)<rrA mniiA I'lrlch 



i The n.-iit -I.I.. of a .mall teetlferou* .pcvlmen. 

 41 to 47. Lateral, cardinal and poaterior view* of *ame. X S 



4k. The right .We of a well praaerved eaat of the Interior of a large example. 

 4*. Cardinal view of aame. x 1 .bowing eoar* of the adductor and pedal muaelea. 



giga a to tt. OraoctowTA >*ffr>*yj, a. *p - *** 



a. BIIMftad right valve of the .peel*, from the middle third of the Treaton ahale*. 



>l II Inge of aame. x t. 



U. Oaat of the Interior from the (ialena ahalea. provlelonally referred to thU apedea. 



Fig*. 51 to 6C. OrannDoXTA icnnti.oi. n. p 



a to it. The left aide and posterior, anterior and doraal view* of a .peclmen preaervlng the .hell and .bowing. 

 among other character* of the apMtoa. the .harply angular umlnual ridge. Ml Idle third of the 

 Trenton abalaa. wear Uaaaoa Falla. Mlaaaanl* 

 57. Hlage of a right valve, xz. 



a. The right aide of a oaat of the Interior from the Galena ebale*. provtolonally referred to thl* peeMa. 

 The anterior end I* larger than In the typical form. 



(Ovca. 



