Oct., 1907. New Crinoids — Slocom. 301 



cup accompanied by a natural mold of which a part of the base 

 is missing. 



Locality : Niagaran limestone of the spoil heaps along the Chicago 

 Drainage Canal near Lemont, Illinois. 



Family CALYPTOCRINID/E. 



EUCALYPTOCRINUS Goldfuss. 

 Eucalyptocrinus obconicus Hall, Plate LXXXVI, Figures 1-2. 



1867 E. obconicus Hall, 20th Rept. N. Y. St. Mus., p. 323, PI. XI, 

 Fig. 1. 



1870 E. obconicus Hall, 20th Rept. N. Y. St. Mus., Rev. Ed., 

 p. 365, PI. XI, Fig. 1. 



1885 E. obconicus Wachsmuth & Sp., Rev. Palaeocr. Pt. Ill, p. 133. 



1897 E. obconicus Wachsmuth & Sp., N. Am. Crin. Cam., Vol. 

 I.,p.353,Pl.LXXXIII,Fig. 13. 



1900 E. obconicus Weller, Bull. 4, Nat. Hist. Surv., Chicago Acad. 

 Sci., p. 109, PI. VII, Fig. 8. 



Dorsal cup obconical, truncated at the base by the attachment for 

 the column ; height nearly twice its diameter at the arm bases ; grad- 

 ually and regularly expanding from the size of the column at its base 

 to the arm bases where it attains its greatest diameter! The plates 

 are thicker in the central portion than at the edges, so that both their 

 inner and' outer surfaces are convex. The outer surface of the plates 

 is smooth and slopes gently towards the sutures. The natural cast is 

 similar in outline to the exterior of the dorsal cup, but it is pointed at 

 the base. The position of the sutures is indicated by low angular ridges 

 which are formed by the convexity of the inner surface of the plates. 



Basals four, three pentagonal, one hexagonal, long and narrow. 

 Together they form a cup, height and width about equal. Radials 

 five, the largest plates in the calyx; four heptagonal, the other hexag- 

 onal, about equal in size and nearly twice as high as wide. First cos- 

 tals quadrangular, higher than wide, proximal and lateral edges arched, 

 distal edges much narrower than the proximal ones. Second or axial 

 costals are in the form of a regular pentagon, somewhat smaller than 

 the first costals. Distichals four to each ray. The first pair hexagonal, 

 in contact with each other and about the size of the second costals 

 upon which they rest. The second pair is very small. First inter- 

 brachials ten-sided, about twice as high as wide and next to the radials 

 in size. These are followed by two long narrow plates, with their 

 longest edges in contact. Interdistichals small, angular below and 



