258 PROCEEDINGS OF THE ACADEMY OP [1879. 



1842. Ichthyocrinus lsevis Conrad (not Angl.) Type for the genus. Journ. Acad. 



Nat. Sci. Philad., vol. xiii. p. 279, pi. 15, fig. 16; also 1852, Hall, Pal. N. 



York, vol. ii. p. 195, pi. 43, fig. 2. Niagara gr. Lockport, N. Y. 

 1878. Ichthyocrinus nobilis Wach. & Spr. Proceed. Acad. Nat. Sci. Philad., p. 



254. Upper Burl, and Keokuk transition bed. Burlington, Iowa. 

 1839. Ichthyocrinus pyriformis Phillips. (Cyathocr. pyriformis.) Sil. System, 



p. 672, pi. 17, fig. 6; also Iconogr. Crin., p. 13, pi. 17, fig. 6; and pi. 22, 



fig. 22. Upper Silur. England and Sweden. 

 *1852. Ichthyocrinus simplex Hall. (Lecanocr. simplex.) Geol. Rep. N. York, 



vol. ii. p. 202. pi. 44, figs. 2 a, b, e. Niagara gr. Lockport, N. Y. 



Hall's figure evidently represents a young Ichthyocrinus, and 

 not a young Lecanocrinus as he supposed. 



1862. Ichthyocrinus subangularis Hall. Trans. Alban. Inst, Article xii., p. 7. 



Niagara gr. Waldron, Ind. 

 1850. Ichthyocrinus tiarseformis Troost. (Cyathocr. tiarseformis. Troost's Catal., 



and Geol. Rep. Iowa, vol. i., part ii., p. 558. Subcarbon. Tennessee. 



B. Subgenus HOMALOCRINUS Angelin. 

 1878. Iconogr. Crinoid., p. 11. 

 We consider Homalocrinus not sufficiently distinct from Ichthyo- 

 crinus to rank it as a full genus, but propose the name for a division 

 under Ichthyocrinus. The following is a translation of Angelin's 

 generic description : "Body including arms ovoid. Basals three, 

 small. Parabasals five, triangular, placed between the sides of 

 the primary radials. Primary radials transverse, and in the form 

 of a half moon. Interradials three, the lower one heptagonal and 

 laro-e, with two small ones above. Anals three, subequal. Rays 

 several times dichotomizing." Angelin described Ichlhyowinus 

 without interradials or anals, and it seems that upon this feature 

 mainly he separates Homalocrinus. We find, however, in the 

 only known species the anal area slightly different from the inter- 

 radial, and the primary radials, instead of increasing from the" 

 base upward, as is the case in all Ichllujocrini, decrease in the 

 same direction, the first radial being here the larger plate. The 

 latter feature has induced us to retain Homalocrinus subgenerically 

 and place it under Ichthyocrinus, with which it has the closest 

 affinities. 



1878. Homalocrinus parabasilis Angelin. Iconogr. Crin., p. 11, pi. 16, figs. 29, 

 30. Upper Silur. Gotland, Swed. 



2. CLEIOCRINTJS Billings. 



1856. Geol. Surv. Canada, p. 276. 

 1B59. lb. Decade i v., p. 52. 



