54 



formula. The arm formula is like D. saUbrosus, but that spe- 

 cies has a concave dtpression below, and is constricted below 

 the arms, and has two interradials in the second range, and 

 very different surface ornamentation. This species cannot be 

 mistaken for any other, either upon superficial examination 

 or upon close inspection of the number and arrangement of 

 th(! plates. 



Found by Geo. K. Greene in the Hamilton Grouji, neai- 

 C'harlestown, Indiana, and now in the collection of Wm. F. K 

 (iurley. 



nOLATOCRlNUS DTSSIMILARIS, n. sp. 



I'liile Til, Fi<j. 2.'), hasdl rirw; Fie/. 2(i, siimmil view, Ficf. 27, 



(izyi/oHS side vinr. 



Species below medium size, depressed or very short. Caly.N 

 low, about three times as wide as high, rounding out from a 

 d(!ep liasal cavity and spr'eading, without any coiisti'iction be- 

 low the ai'uis and liaving the general form of D. (ip\iliis. Sur- 

 face deeply sculptured. Radial ridges very small and nodes 

 small. The central part of eacli interradial instead of bearing 

 a node is excavated. 



Basal plates within the cavity of the calyx and extend 

 higher than the base of the free arms, funnel-shaped. 

 First primary radials within the funnel-shaped basal cavity 

 and longer than wide. Second primary radials about twice as 

 wide as long, (|uadi'angular. Third primary radials a little 

 larger than tiie .second, twice as wide as long, pentagonal, 

 axillary, and in each ray adjoining the ax.ygous area and in 

 the ray o]iposite the azygous art^a support on one of th<' upiicr 

 sloping sides three secondary radials and upon the other a 

 siiTgle sei'ondary radial, which is axillary and supports on each 

 upper sloping side two tertiary radials, which arrangement 

 gives to each of these rays thj-ee arms. In each of tlie othci- 

 lateral rays the third jiriniary radials support on each u]ipei- 

 side three secondary radials which give to eac'h of these rays 

 two arins. There are, therefore, thirteen arms in this species. 

 It is the proximal side of each ray adjoining tlie azygous area 

 that beai'S the tertiary radials. 



The azygous ai-ea is like tin- otlier areas. The fii-st plate is 

 >omowliat elontratod, lias nini' sides and is truncatiHl liv a sinaie 



