LECAN0CRINIDAE 183 



II. IBr 1. 



Crown usually large. 

 Calyx turbinate. 



Calyx ridges sharp and narrow, no pits at angles, plates fairly thick. 

 IBr moderately wide, arms xather angular. 



R facets often raised, with slight marginal rim. 



Base narrow ; lower part of IBB contracted P. patei. 



Calyx ridges broad and rounded ; shallow pits at angles ; plates massive. 

 IBr rather wide ; arms round and heavy. 

 R facets not elevated and without rim. 



Base wide. IBB not contracted P. biicephalus. 



Calyx ridges obscure ; no pits at angles. 

 IBr narrow — two-fifths the width of R. 



Arms slender, rounded P. tenuibrachiatus. 



III. IBr 3 or more. 

 Crown small. 



Calyx low, hemispheric, without ridges or pits. 



IBr moderately wide ; arms relatively much longer than 



in other species P. zvelleri. 



Species Imperfectly Known 

 IBr unknown. 



Calyx ridges present. 



IBB very large ; calyx turbinate P. americanus. 



IBB small, largely hidden by the column P. canadensis. 



Column tapering gradually from calyx; surface smooth ( ?)P. dubius. 



Pycnosaccus scrobiculatus (Hisinger) 

 Plate XI, figs, i-io 



Cyathocrinites scrobiculatus Hisinger, Lethaea Suecica, Supp., II, 1840, p. 6, pi. 39, figs. 4a, b> c; 



Anteckningar i Physik och Geog., pt. 7, 1840, p. 45. — Bather, Ann. and Mag. Nat. Hist., (6)V, 



1890, pp. 387, 388; Crinoidea of Gotland, 1893, p. 12. 

 Pycnosaccus scrobiculatus, Angelin, Icon. Crin. Sueciae, 1878, p. 14, pi. 15, figs. 10, 11. — Wachsmuth and 



Springer, Revision Palaeocrinoidea, pt. 1, 1879, p. 41. 

 Pycnosaccus ? costatus Angelin, Icon. Crin. Sueciae, 1878, p. 14, pi. 15, fig. 13. 



Type of the genus. 



Specimens generally small. Calyx turbinate, with straight sides, wider 

 than high; average height to width about i to 1.6; base broad and truncate, 

 spread from base to top of R, I to 2.8. The calyx plates are strong, marked by 

 sharp, elevated neural ridges passing from below the radial facets to centers of 

 basals, and from there diverging again to the infrabasals, usually also hori- 

 zontally from center to center of radials; these ridges divide the surface into 

 large triangular and rhombic areas with their angles at the centers of the 

 plates, leaving depressions in the middle of these areas where three sutures meet. 

 Calyx of size usually found, about 14 mm. high by 23 mm. wide; base, 8 mm.; 

 an unusually large specimen is about 18 mm. high by 30 mm. wide in a flattened 

 condition. 



