NO. 3 ON THE FOSSIL CRINOID FAMILY CATILLOCRINIDAE 25 



Mycocrinus conicus n. sp. 

 Plate I, figs. 1 1- 13 



BB more than half the height of cup, and about as wide at the basi- 

 radial suture ; not forming a prominent knob, but a cone sloping 

 about evenly with the ring of radials ; one interbasal suture visible, 

 opposite r. post. R. Transverse outline of cup about circular. Diam. 

 5.5 mm. ; height 5 mm. ; arms ii. 



Founded on a specimen in the author's collection from Nollenbach 

 in the Eifel. 



CATILLOCRINUS (Troost) Shumard 



Catal. Pal. Foss. Trans. Acad. Sci., St. Louis, II, 1866, p. 357. — Meek and 

 Worthen (Nematocrinus), Proc. Acad. Nat. Sci. Phil., 1866, p. 251; 

 Geol. Surv. 111., Ill, 1868, p. 465; V, 1873, p. 504.— Wachsmuth and 

 Springer, Rev. Pal. pt. 3, 1866, p. 268. — Bather, Crin. Gotl.. 1893, p. 25 ; 

 Lankester Zool., pt. 3, 1900, p. 150. — Zittel-Eastman, Text-book Pal., 

 1896, p. 153. — Jaekel, Crin. Deutschl., 1895, p. 44. — Wood, Bull. 64, U. S. 

 Nat. Mus., 1909, p. 23. — Wanner, Perm. Echin. Timor, 1916, p. 6. 



Cup broadly truncate above and below, with column facet cover- 

 ing almost the entire base. Base not protruding conspicuously but 

 forming a low disk, usually flat, or projecting more or less unequally 

 above the column ; composed primarily either of five basal plates, 

 usually anchylosed or compressed, with sutures invisible or obscure, 

 and enclosing a circlet of three small infrabasals ; or of a single 

 circlet of three unequal plates, the smaller one in left posterior 

 position. One of the small RR (r. post.) rectilinear; r. ant. R 

 triangular with one side curved ; 1. ant. R heart-shaped or narrow 

 triangular ; each bearing a single arm. The two large RR usually 

 occupying 80 to 90 per cent of perimeter at upper edge of cup, and 

 bearing a like proportion of the arms ; 1. post. R. to ant. R as 

 I to 1.4. Exception as to form and proportions of RR in C. car- 

 pent eri. Transverse outline of cup usually elliptic. Arms in contact 

 all around, except where separated for a short distance at posterior 

 side by anal or tube plate ; their number varying with species and with 

 individual growth. Anal tube large, massive, extending to or beyond 

 the ends of arms. Column round, with proximal enlargement of 

 short columnals, tapering and becoming longer distalwards. 



Dimensions : Long diameter of cup 2.5 to 27 mm. ; height 2 to 10 

 mm. Number of arms 13 to 58. 



Genotype. — C. tennesseeae (Troost) Shumard. Six species; four 

 described heretofore, and two here proposed as new. 



Distribution. — Lower Carboniferous, Mississippian, from the earli- 

 est to the latest member. Interior continental area of North America. 



