PLATE IV T. 



Ley'eiid. pa. Posterior adductors. p. Parietal impi-ession. 



aa. Anterior adductors. m. Median impressions, 



da. Dorsal adjustors. Ii. Bracliial muscular impression. 



\'a. Ventral adjustors. v. Vascular trunks, 



nun. Mesenteric muscular impression. v'. Vascular branches. 



CKANIELLA, CEhlert. 



I'iij^e 153. 



Ckaniella Ulkichi, sp. nov. 



Fig-. 1. A cast ol the interiui- of a lowei- valve, somewhat restored on the rig-ht .«ide ; showing- the strong- 

 anteri. r and vei'y obscure posterior adductor impressions, and the mai-ks of the vascular sin- 

 uses. The shell is convex and shows no evidence of attachment, though the external surface is 

 ovei-grown with a bryozoan. Di-awn from a gutta-pei-cha cast of a natural interior. X 1.5. 

 Trenton limestone. Minneapolis, Minntsota. 



Fig-. 2. The mternal cast of an upper valve, belie\-ed to be of the same species. The sigmoid vasculai' 

 impressions are simplei- fliau elsewhere observed ; the scars of the dorsal adjustors and of 

 muscles accessm-y to the anterior adductors (possibly the bra(;hial muscli^s) are also apparent. 

 Drawn from a gutta-percha c;ist of a natural interioi-. X 1.5. 

 Trenton limestone. Mbaieapolls, Minnesota. 



Ce.\niell.\ Hamiltoni/e, Hall. 



Fig. ii. The interior of a lower valve atta(;hed to a SruEFTKLASMA ; showing the usual character of the 

 muscular scars, viz , anterioi- and posterior adductors, the ventral adjustors, and post-median 

 or mesenteric impression ; also the characteristic radiating vascular siiuises. 

 Hamilton group. Canandaigua Lake, N. Y. 

 Fig. 4. The interior of an upper valve. 



Coi-niferous limestone. Falls of file Ohio. 

 The interior of an attached valve. From Palceontology of New York, vol. iv, \i\. iii, tig. 23. 

 Three individuals of diffei-ent sizes, attached to the surface of TropldoUptus caii/tatus. Operu 

 citato, pi. iii, tig. 19. 



Hamilton group. IVe-Hern New York. 

 The interior of a lower vahe ; showing the usual muscular and vascular impressions, and very 



great thickening of the shell. X 2. 

 An upper valve ; showing the modification of the surface from attachment to an individual of 



SpiriftT audactdus. 

 Profile view of a normal shell, attached to Tropidoleptus carinatus. 



Hamilton gi-oup. CanandaigvM Lake, iV. Y. 

 The exterior of an upper valve. From Thirteenth Rept. State Cab. Nat. Hist., ji. 7t), tig. 3. 1860. 



Hamilton group. Western New York. 

 An upper valve, modified by attachment to the posl>-lateral portion of a right valve of Cypricardelta 

 {Microdon) helli.s-triala. 



Hamilton group. Canandaigua Lake, N. Y. 

 An individual gi-eatly modified l)y attachment to Tropidoleptus carinatus. 



An internal cast of a large upper valve; .showing the usual nuiscular scars and the peculiar 

 sigmoid vascular trunks with their ramihcations. 

 Hamilton group. Pratt's Falls, N. Y. 

 An internal cast of a very convex upper valve, greatly moditieil by attachment. X 2. 



Hamilton group. Canandaigua Lake, N. Y. 

 An intei-nal cast of an upper valve; showing the characteristic impressions. X 2. 



Hamilton group. Bellona, N. Y. 

 An internal cast of a convex and apparently free lower valve ; .showing the closer approximation 

 of the anterior and posterior adductoi- scars than in the oppo.site valve, the deep impi-i'sssion of 

 the mesenteric muscle, and the radiating vascular sinuses. The figure is sligditly restored on 

 the left side. X 2. 



Hamilton gi-onp. Centerfield, N. Y. 



PHOLIDOPS, Hall. 

 Phohdops Tkentoxensis, Hall. 



Fig. 17. A slightly crushed specimen. X 4. 



Trenton limestone. Middletrille, N. Y. 



Pholidoi's Cincinnaten'.sis, Hall. 



Fig. 18. The exterior of a normal sjiecimen. X 4. 



Hudson River group. Cincinnati., (Viio. 



