294 SMITHSONIAN INSTITUTION 



CLIDOCHIRUS Angelin 

 Plate XXXVII 



Clidochirus Angelin, Icon. Crin. Sueciae, 187S, p. 12. — Wachsmuth and Springer, Revision Palaeocri- 

 noidea, I, 1879, p. 39. — Von Zittel, Handbuch Palaeontologie, I, 1879, p. 355. — Bather, Rep. British 

 Assoc, for 1898 [1899], p. 923; Treatise on Zoology (Lankester), pt. 3, 1900, p. 188. — Springer, 

 Araer. Geologist, XXX, 1902, p. 94; Jour. Geology, XIV, 1906, pp. 479, 516. — Zittel-Eastman, Text- 

 book Paleontology, 1913, p. 204. 



Fig. 38. Clidochirus 



Ichthyocrinidae with rays in contact except in lower part at the posterior 

 side. Crown elongate, expanding above radials. Radianal in primitive position 

 under right posterior radial, resting on basals and touching right anterior 

 radial. Inf rabasals variable ; either large, exposed above the column, or small, 

 entirely concealed. Basals large, exposed above the column. Anal x alone, or 

 followed by others in single vertical series, arched over by brachials. Primi- 

 brachs two. Arms dichotomous, interlocking. Column large, with or without 

 proximal enlargement. Otherwise similar to Ichthyocrinus. 



Genotype. Clidochirus pyrum Angelin. 



Distribution. Silurian to Devonian (Lower Carboniferous?) ; Sweden and 



the United States. 



This genus was founded by Angelin 1 upon a single species and specimen from bed c 

 at Wisby, Gotland. His generic diagnosis, translated, is as follows : 



Body short, pyriform. Calyx cyathoid, inequilateral. Radials variable, three or four. Anals dis- 

 tinct, four, in a longitudinal series. 



This would have been well enough as far as it goes if given in connection with a correct 

 definition of Ichthyocrinus, although it does not agree with his specific description, nor with 

 the facts in regard to the number of anal plates in the series. But Angelin' placed it under a 

 new family, Homalocrinidae, along with Lecanocrinus and Calpiocrinus, without recogniz- 

 ing its close relation to Ichthyocrinus, although he figured under /. piriformis {op. cit., 

 pi. 22, fig. 6) an excellent specimen of his type species Clidochirus pyrum (see my PI. XXXVII, 

 figs. 30, b). His account of the genus contained nothing as to the composition of the base, 



1 Iconocraphica Crinoideorum Sueciae, 1878, p. 12. 



