LECANOCRINIDAE 1 57 



structure, and proof of the absence of a radianal, is a fragment in the Riks Museum. The 

 reasons for associating these three specimens have been given in the generic discussion. No 

 others have been found. 



Types. Author's collection, British Museum, and Riks Museum, as above stated. 



Horizon and locality. Silurian, Wenlock Group ; Dudley, England, and Gotland, Sweden. 



Calpiocrinus ovatus Angelin 

 Plate VII, figs, qa-f 



Calpiocrinus ovatus Angelin, Icon. Crin. Suec, 1878, p. 12, pi. 16, figs. 17-19. — Wachsmuth and Springer, 

 Revision Palaeocrinoidea, pt. r, 1879. p. 39. — Springer, Jour. Geology, XIV, 1906, pi. 7, fig. 4. 



Specimens small. Crown ovoid, broadly rounded below, widest about axil- 

 lary IIBr, where height to width is about i to 2; at IAx, 1 to 3. Plates evenly 

 curved and but little convex ; surface smooth. Height of crown, 26 mm. ; width, 

 18 mm. ; base, 5.5 mm. 



IBB large, forming a broad, truncate base, concealing all BB except apex 

 of post. B. IIBr 3; IIIBr 4 or 5. All Br much wider than high. Rami nearly 

 equal; ramules from outer arms prominent from every third or fourth Br, those 

 from inner arms inconspicuous, borne upon small faces toward ventral side of 

 axillary Br; outer arms diminishing by steps, inner by gradual taper. Arms 

 closely abutting between rays and ray divisions, infolding about fifth ramule to 

 a rather narrow apex. Anal x rather larger than other iBr, followed by two or 

 more plates ; first plate in other iBr areas followed by one or more plates in single 

 series. Column unknown. 



This species with C. heterodactylus exhibits the smallest departure from typical Calpio- 

 crinus in the line of transition toward Homalocrinus. The inner arms of the ray are almost as 

 large as the outer, differing only in the more gradual taper, and more feeble development of 

 lateral ramules which are rarely visible from the dorsal side. This form is readily distin- 

 guished from C. Umbriatus and C. rotundatus by the above characters, and by the relatively 

 heavier arms and shorter intervals between ramules. We have no proof of the presence or 

 absence of a radianal, the basal development being such that it could not be seen if present; 

 from analogy with C. intermedins we assume that it is not. No other specimen but the type 

 has been found. 



Type. In the Riks Museum, Stockholm. 



Horizon and locality. Silurian, Wenlock Group, horizon /; Gotland, Sweden. 



Calpiocrinus heterodactylus Angelin 

 Plate VII, figs. $a-e 



Calpiocrinus heterodactylus Angelin, Icon. Crin. Suec, 1878, p. 12, pi. 3, fig. 10, not pi. 26, fig. 8. — 

 Wachsmuth and Springer, Revision Palaeocrinoidea, pt. 1, 1879, p. 39. — Springer, Jour. Geology, 

 XIV, 1906, pi. 7, fig. 3. — Waagen and Jahn in Barrande, Syst. Silur. centre Boheme, VII, pt. 2, 

 1899, p. 22. 



Similar to C. ovatus; differing mainly in having a narrower and less ovoid 

 crown, and in the slightly less development of interbrachial plates. The struc- 

 tural details of this form are sufficiently explained under the last species and in 



