1879.] NATURAL SCIENCES OP PHILADELPHIA. 275 



crease in size gradually upward, the lower one being about half 

 the size of the primary radials. 



Axillary plates from ten to twenty and more, with occasionally 

 one to three within the axil of the tertiary radials. Anal area 

 without lateral proboscis or visible aperture, slightly wider than 

 the interradial areas and similarly arranged, with generally two 

 plates in the first series instead of one. Dome unknown, but 

 evidently to some extent flexile. Column large, tapering down- 

 ward, with very thin joints next the body ; central perforation of 

 medium size, pentagonal. 



The most important distinction between Forbesiocrinus and 

 Taxoorinus is to be found in the construction of the anal and 

 interradial areas. Unfortunately the type specimen of the former 

 genus is in these particular parts very imperfect. We therefore 

 propose, until better specimens of Forbesiocrinus nobilis De Kon. 

 & Leh. are discovered, to make Forbesiocrinus Agassizi Hall the 

 type of the genus. This large and beautiful species from the 

 Burlington limestone evidently belongs to the same group, and 

 has been found in excellent preservation. 



Geographical and Geological Distribution. Forbesiocrinus is 

 not distinguished for a great variety of form, nor for abundance 

 of individuals. In Europe, there has been found only one species 

 from the Mountain limestone of England In the United States, 

 it is represented by four species, all from the Subcarboniferous. 



We recognize the following species as belonging to this genus : 



1858. Forbesiocr. Agassizi Hall. (Proposed type). Geol. Rep. Iowa, vol. i., pt. 2, p- 



631; also Suppl. Iowa Geol. Rep., p. 65. Upper Burlgt. limest. Burling- 

 ton, Iowa. Syno7i. F. Agassizi var. giganteus, Meek & Worth. Geol. Rep. 

 Illinois, vol. iii. p. 495, p!. 18, fig. 3. 



1859. Forbesiocr. Cestriensis Hall. Suppl. Geol. Rep. Iowa, p. 68. Chester limest. 



Pope Co., 111. 

 1853. Forbosiocr. nobilis De Kon. & Leh. (original type). Recherches s. 1. Crin. 



Belg. p. 121, pi. 2, figs. 2 a, b. Poteriocr. nobilis Phill. is probably a 



synonym. Mountain limest. Yorkshire, Engl. 

 1858. Forbesiocr. Wortheni Hall. Geol. Rep. Iowa, vol. i., pt. 2, p. 632, pi. 17, 



fig. 5. Keokuk limest. Keokuk, Iowa, and Crawfordsville, Ind. 



B. Subgenus LITHOCRINUS Wachs. & Spr. 

 (m&o?, a stone ; *fiw, a lily.) 



Prof. Angelin, in the Iconogr. Crinoid. Suec, p. 9, has described 

 several Gotland species under Forbesiocrinus, which we propose 



