LECANOCRINIDAE 1 45 



CALPIOCRINUS Angelin 

 Plates VII, VIII 



Calpiocrinus Angelin, Icon. Crin. Sueciae, 1878, p. 12. — Wachsmuth and Springer, Revision Palaeoc- 

 rinoidea, pt. 1, 1879, p. 38 ; ibid., pt. 3, 1886, p. 143 ; Proc. Acad. Nat. Sci. Phil., Nov., 1888, p. 357 ; 

 ibid., 1890, p. 388. — Von Zittel, Handbuch Palaeontologie, I, 1879, p. 356; Grundzuge Palaeontology, 

 1895, p. 138. — Zittel-Eastman, Textbook Palaeontology, 1896, p. 164 (2d Pd., 1913, p. 203). — 

 Jaekel, Zeitschr. deutsch. geol. Ges., XLIX, 1897, p. 46 (separate). — VVaagen and Jahn in Bar- 

 rande, Silur. Syst. centre Boheme, VII, 1899, P- 20 - — Bather, Rep. British Assoc, for 1898 [1899], 

 p. 923; Geol. Mag., (4) VIII, Aug., 1901, p. 378; Treatise on Zoology (LankesterJ, pt. 3, 1900, 

 p. 189. — Springer, Amer. Geologist, XXX, 1902, p. 95; Jour. Geology, XIV, 1906, p. 480. 



Fig. 14. Calpiocrinus 



Lecanocrinidae with rays above radials partly separated by solid plates 

 arched over by brachials, and with highly specialized base. Crown ovoid. 

 Inf rabasals very large, enveloping basals, and to a variable extent radials and 

 part of primibrachs. No radianal. Anal x followed by others. Interbrachials 

 one large single plate, or several smaller ones in succession. Arms heteroto- 

 mous ; rays divided into twenty main rami abutting above interbrachials, bear- 

 ing ramules inside of dichotom. Column large, short, tapering gradually to an 

 encrusting root. 



Genotype. Calpiocrinus fimbriatus Angelin. 



Distribution. Silurian, Wenlock beds ; Gotland, Sweden. 



The two foregoing genera represent a specialization distinct from anything observed 

 elsewhere among the crinoids, under the influence of which they shade into one another to 

 some extent ; therefore they may be discussed together. Considering that they have a definite 

 and highly differentiated structure, no type of crinoids has been more misunderstood than 

 that represented by Homalocrinus and Calpiocrinus. That it can be better understood now is 

 due largely to the careful working up of the material for structural details, and their in- 

 structive illustration, by Mr. Liljevall. 



The dominant developmental feature in these two forms is the extraordinary enlarge- 

 ment of the usually inconspicuous and sometimes transitory element, the infrabasals, which is 

 carried to an extreme in both genera. Angelin gave an unusually long diagnosis of Calpio- 



