PLATE IV i. 
Legend, pa. Posterior adductors. 
aa. Anterior adductors, 
da. Dorsal adjustors, 
va. Ventral adjustors, 
mm. Mesenteric muscular impression. 
CKANIELLA 
p. Parietal impression, 
m. Median impressions, 
b. Brachial muscular impression, 
v. Vascular trunks. 
v'. Vascular branches. 
(Ehlert. 
Page 153.. 
Craniella Ulrichi, sp. 110V. 
Fig. 1. A cast of the interior of a lower valve, somewhat restored on the right side ; showing the strong 
anterh r and very obscure posterior adductor impressions, and the marks of the vascular sin¬ 
uses. The shell is convex and shows no evidence'of attachment, though the external surface is 
overgrown with a bryozoan. Drawn from a gutta-percha cast of a natural interior. X 1.5. 
Trenton limestone. Minneapolis, Minnesota. 
Fig. 2. The internal cast of an upper valve, believed to be of the same species. The sigmoid vascular 
impressions are simpler than elsewhere observed ; the scars of the dorsal adjustors and of 
muscles accessory to the anterior adductors (possibly the brachial muscles) are also apparent. 
Drawn from a gutta-percha cast of a natural interior. X 1.5. 
Trenton limestone; Minneapolis, Minnesota. 
Craxiella Hamiltoni^, Hall. 
Fig. 3. The interior of a lower valve attached to a Streptelasma ; showing the usual character of the 
muscular scars, viz., anterior and posterior adductors, the ventral adjustors, and post-median 
or mesenteric impression ; also the characteristic radiating vascular sinuses. 
Hamilton group. Canandaigua Lake, N. Y. 
Fig. 4. The interior of an upper valve. 
Corniferous limestone. Falls of the Ohio. 
Fig. 5. The interior of an attached valve. From Palaeontology of New York, vol. iv, pi. iii, fig. 23. 
Fig. 6. Three individuals of different sizes, attached to the surface of Tropidoleptus carinatus. Opero 
citato, pi. iii, fig. 19. 
Hamilton group. Western New York. 
Fig. 7. The interior of a lower valve ; showing the usual muscular and vascular impressions, and very 
great thickening of the shell. X 2. 
Fig. S! An upper vaive ; showing the modification of the surface from attachment to an individual of 
Spirifer audaculus. 
Fig. 9. Profile view of a normal shell, attached to Tropidoleptus carinatus. 
Hamilton group. Canandaigua Lake, N. Y. 
Fig. 10. The exterior of an upper valve. From Thirteenth Rept. State Cab. Nat. Hist., p. 76,fig. 3. 1860. 
Hamilton group. Western New York. 
Fig. 11. An upper valve, modified by attachment to the post-lateral- portion of a right valve of Cypricardella 
( Microdon) bellistriata. 
Hamilton group. Canandaigua Lake, N. Y. 
Fig. 12. An individual greatly modified by attachment to Tropidoleptus carinatus. 
Fig. 13. An internal cast of a large upper valve; .showing the usual muscular scars and the peculiar 
sigmoid vascular trunks with their ramifications. 
Hamilton group. Pratt’s Falls, N. Y. 
Fig. 14. An internal cast of a very convex upper valve, greatly modified by attachment. X 2. 
Hamilton group. Canandaigua Lake, N. Y. 
Fig. 15.. An internal cast of an upper valve ; showing the characteristic impressions. X 2. 
Hamilton group. Bellona, N. Y. 
Fig. 16. An internal cast of a convex and apparently free lower valve ; showing the closer approximation 
of the anterior and posterior, adductor scars than in the opposite valve, the deep impresssion of 
the mesenteric muscle, and the radiating vascular sinuses. The figure is slightly restored on 
1 • the left side. X 2. 
Hamilton group. Centerfield, N. Y. 
PHOLIDOPS, Hall. 
Page J55. . 
Pholidops Trenton ensis, Hull. 
Fig-. 17. A slightly crushed specimen. X 4. 
Trenton limestone. Middleville, N. Y. 
Pholidops Cincinnatensis, Hull. 
Fig. 18. The exterior of a normal specimen. X 4. 
Hudson River group. Cincinnati, Ohio. 
