Dec, 1920] Cystids and Blastoids 43 



Since the numbered specimen shows poor traces of the ambulacral 

 system and the wax cast shows excellent evidence of the character of the 

 latter it is assumed that it came from the same locality. The wax cast 

 was made by pouring the wax into a natural mold of the exterior of a 

 specimen, the cracks between the fragments of the matrix showing dis- 

 tinctly. It exposes the top of the specimen with its five ambulacral rays. 

 The anal aperture is clearly defined, its margin protruding slightly. 

 The right posterior ray branches just above the level of the anal aper- 

 ture, the tips of the two branches reaching within 3 or 4 mm. from the 

 attachment area of the column. The right anterior ray branches at 

 about the same level, the tip of the right hand branch extending as far 

 down as the others mentioned. The anterior ray is moderately distinct 

 as far as its point of branching ; its branches may have reached opposite 

 sides of the pectinirhomb on plates 1-5. Only the proximal part of the 

 left anterior ray remains. The left posterior ray is clearly defined for 

 about two-thirds of the height of the theca downward, but a faint trace 

 of its right-hand branch indicates that its tip reached within 5 mm. of 

 the attachment area for the column. The right posterior ray shows 

 clearly the short lateral branches of the food-grooves traversing the 

 rays and their branches, but the attachment areas for the brachioles are 

 not indicated. Lateral branches of the food-grooves, leading to the 

 brachioles, are visible also on the right anterior and left posterior rays. 

 Three or four lateral branches are seen on each side of the proximal or 

 undivided parts of the rays, about 10 occurring on each side of the 

 branches. The ornamentation of the surface is indistinctly presented. 

 The base of the specimen is not invaginated at all, as viewed from the 

 exterior, but there is a faint quadrangular appearance there where the 

 quadrangular margin of the deeply invaginated base of the cast of the 

 interior should appear. It is evident that the invagination is a charac- 

 teristic of the interior and is accompanied by an immense thickening of 

 the thecal plates "within this invaginated part. 



This explains the absence of invagination also on the exterior of the 

 base of the second specimen found at Cedarville, Ohio, here figured 

 (Plate II, Fig. 8), which at first puzzled the writer. 



The attachment area of the Chicago specimen just described is 

 9 mm. in diameter. 



Locality and Horizon. — -From the Racine dolomite at 

 Racine, Wisconsin, and in the Chicago area of Illinois. Also 

 from the Cedarville dolomite at Cedarville and Wilmington, 

 Ohio. 



Both in the Cedarville dolomite of Cedarville, Ohio, and in 

 the Racine dolomite of the Chicago area, there is a small cystid, 

 about 15 mm. in diameter, which appears to be a new species of 

 Ccelocystis. The circum-oral plates or deltoids, forming the 

 fourth row of the theca, are relatively large. The pectinirhombs 

 on plates 12-18, and 14-15, and the plates surrounding the anal 

 aperture are well defined, but the base is not well exposed in 

 any of the specimens at hand. 



