450 THE CEINOIDEA CAMERATA OF NORTH AMERICA. 



the anterior side the base of the ventral tube, which is ahnost central, and 

 more slender than usual in this genus. 



Horizon and Locality. — Lower Burlington limestone ; Burlington, Iowa. 



Ti/pe in the (Worthen) Illinois State collection, Springfield. 



Remarks. — The specimen from which Hall made his description was 

 defective, and the arm formula which he gives of the species is incorrect. 

 It has normally but fourteen arms : i^; but when an additional arm is intro- 

 duced, whicli is quite often the case, this is placed in the antero-lateral rays, 

 and not in the posterior one. Hall gave the arm formula as i^. 



Macrocrinus verneuilianus (Shum.). 

 Plate XXX. Figs. 15, 16, 17, 18. 



1855. Actinocrims verneuiliaiim — Shumard; Geol. Surv. of Missouri by Swallow, Part H., p. 1933, 



Plate A, Pigs. \a, h. 

 1873. Batocrimis vemeuiliaims Meek and Woethen ; Geol. Rep. Illinois, Vol. T., p. 379, Plate i, Pigs. 3 



and 4. 

 1881. Eretmocriniis verxexiliaxns — W. and Sp. ; Revision Palteocr., Part II., p. 173 (Proceed. Acad. Nat. 



Sci. Phila., p. 347). 

 1890. Eretmocrimis vemeiiiliamis — S. A. Millek; North Amer. Geol. and Paloeont., p. 243. 



Calyx biturbinate, higher than wide ; the dorsal cup higher than the 

 ventral disk, truncate at the base, its sides a little concave, the arm-bearing 

 plates projecting. Surface of plates flat or very slightly convex, the radials 

 and first interbrachials always more or less elevated at the median portions. 



Baisals rather large, forming a hexagonal cup with erect sides ; grooved 

 at the interbasal sutures ; the column facet deep and nari'ow, occupying but 

 one third the diameter at the bottom of the calyx. Radials twice as large 

 as the two costals together, somewhat variable in form, but generally as long 

 as wide, and the lateral faces considerably longer than the upper sloping 

 faces; the two heptagonal plates larger than the hexagonal ones. First 

 costals quadrangular, very small, twice as wide as long ; the second some- 

 what larger and pentangular. Distichals two in both divisions of the anterior 

 ray, and also in one division of the other raj^s ; the other division has but 

 one distichal, which is axillary, and supports 2X2 small palmars ; there 

 being normally fourteen arms, with variations from fourteen to eighteen. 

 First palmars in lateral contact with each other and with adjoining dis- 

 tichals, except at the anal side ; while the upper plates meet only their 

 fellows of the same ray, being entirely free at one side. Arm openings 

 directed slightly upwards ; the interspace between the posterior rays wider 



