'236 The Ohio Journal of Science [Vol. XVII, No. 7, 



In the type of Apiocyslis imago, however, plate 3 is represented by 

 two plates. The one alternating with the bases of plates 8 and 9 is 

 completely preserved, and the other, alternating with the bases of plates 

 7 and S, is preserved for at least two-thirds of its width. Plates 9 and 5 

 are in contact with the bases of plates 15 and 16 respectively, being 

 truncated by the latter. Plates S and 19 also truncate each other. 

 Plate 24, on the contrary, does not appear to truncate plate 13, and the 

 division of plate 23 into two distinct plates could not be verified in this 

 type specimen, even the outlines of this plate being obscure. The 

 pectinirhombs on plates 14 and 15 apparently were small and discrete, 

 the intervening distance being about 5 millimeters. The cast of the 

 anal orifice is protuberant, and the gut passed from this orifice downward 

 and a little toward the right for a distance of at least 5 mm., the right 

 margin of the cast of the passage along the interior of the theca being 

 more sharply defined on the right side. 



Apparently there are obscurely defined remnants of the ambulacral 

 ray No. 5. which terminates at the top of plate 19. There are also 

 weakly defined depressions between plates 20 and 21, and between 

 plates 21 and 22, terminating at the tops of plates 15 and 16 respectively, 

 which suggest the fonner presence here of rays No. 4 and 3. If these 

 observations are correct, they would confinn Schuchert's reference 

 of HaUicystis to the ApiocystincB. 



The exterior of the thecal plates apparently was moderately angu- 

 lated; the direction of the angulations is indicated on the diagram by 

 means of dotted lines. On the basal plates, the median angulation is 

 rather prominent at its lower end. 



HaUicystis imago occurs in the Racine dolomite, in the 

 Niagaran division of the Silurian, at Racine, Wisconsin. 



Callocystites jewetti-elongata, var. nov. 

 PlateXI,Figs. 6A, 6B,3. 



The internal cast of the theca, (Figs 6 A, B), presenting distinct 

 outlines of all of the plates excepting those on the anal side, is at hand. 

 Even on the anal side sufficient traces remain to warrant the diagram 

 here presented, which evidently is that of a typical Callocystites. The 

 line of separation between plates 13 and 24 is unknown, and the double 

 character of plate 23 can not be determined. That half of the pectin- 

 irhomb which is on plate 15 is triangularly lunate, and its nearest part 

 is one millimeter from the intermediate suture line; the other half is 

 nearer, but its outline is indistinct. That half of the pectinirhomb 

 which is on plate 5 is slightly incurved on the proximal side, and its 

 nearest part is slightly over 3 mm. from the intermediate suture line; 

 the other half is 3 mm. from the suture line, but its outline is distinctly 

 preserved. 



Found in the Cedarville colomite at Cedarville, Ohio. 



