262 PROCEEDINGS OF THE ACADEMY OF [1879. 



the bilateral symmetry of the calyx, and the longitudinal arrange- 

 ment of the anal plates, are the most prominent characters of the 

 genus. 



Angelin, on the same page, describes the genus Clidochirus 

 with a single species, which agrees with Calpiocrinus in every 

 respect, except that it has no interradial plates, and four instead 

 of three first radials variations which may be expected even in 

 the same species. 



Geological and Geographical Distribution. Found thus far 

 only in the Upper Silurian of Gotland, where the following species 

 have been discovered: 



1878. Calpiocrinus fimbriatus Angelin. Iconogr. Crinoid., p. 12, pi. 29, figs. 77 



a, b. Upper Silur. Gotland, Swed. 

 1878. Calpiocrinus heterodactylus Angelin. Iconogr. Crinoid., p. 12, pi. 3, fig. 



10 a; and pi. 26, fig. 8. Upper Silur. Gotland, Swed. 

 1878. Calpiocrinus humilis Angelin. Iconogr. Crinoid., p. 12, pi. 23, figs. 28 a-c, 



and pi. 26, fig. 17. Upper Silur. Gotland, Swed. 

 1878. Calpiocrinus ovatus Angelin. Iconogr. Crinoid., p. 12; pi. 16, figs. 17-19. 



Upper Silur. Gotland, Swed. 

 *1878. Calpiocrinus pyrum Angelin. (Clidochirus pyrum). Iconogr. Crinoid , 



p. 12, pi. 22. fig. 23. Upper Silur. Gotland, Swed. 



5 LECANOCRINUS Hall. 



1852. Lecanocrinus, Hall. Geol. Rep., N. Y., vol. ii. p. 199. 



1867. Lecanocrinus, Shultze. Monogr. Echinod. Eifl. Kalkes, p. 40. 



1678. Lecanocrinus, Angelin. Iconogr. Crinoid., p. 12. 



A. Typical firm. 



General form of body and arms suhglobose to pyriform. Calyx 

 bowl-shaped, unsymmetrical, plates heavy. 



Underbasals three, unequal in size, larger than generally found 

 in the family. Basals five, three pentagonal or hexagonal, the 

 two others having an additional side for the lateral insertion of a 

 small anal plate. Primary radials two or three by five, very short 

 and wide, the first one largest. Secondary radials one to three 

 or more, varying in number even in the individual. Arms pre- 

 cisely as in Ichlhyocrinus. Inter radials generally absent. Anal 

 plates two, the lower one lying obliquely toward the right 1 side of 



1 It is worthy of note that in all Paleocrinoids, so far as observed, in 

 which the anal arrangement is unsymmetrical, the odd plates are pushed 

 out toward the right, never to the left. 



