58 The Ohio Journal of Science [Vol. XXI, No. 2, 



Racine specimens. — Gomphocystites bownockeri occurs also in the 

 Racine dolomite of the Chicago area. Several specimens, numbered 

 22944, are preserved at Chicago Univesrity. The one marked 22944A 

 shows the row of laterally compressed plates, along the lower side of 

 one of the food-grooves, very well. The thickness of the thecal plates 

 is almost 2 mm. The middle layers of most of the plates have weathered 

 away, leaving the fillings of some of the diplopores exposed in the form 

 of columns. The exterior layers of a sufficient number of these plates has 

 been preserved to indicate that the food-grooves are relatively narrow, 

 only a millimeter or less in width, but rather sharply impressed; on casts 

 of the interior of the theca they are only faintly indicated. At one 

 point, several short lateral branches of the food-grooves seem to be 

 present. 



In a specimen numbered 4523 at the U. S. National Museum, short 

 lateral grooves branch off diagonally from the lower side of the main 

 food-grooves and terminate at small facets, evidently for the support 

 of brachioles. The combined length of the branches with the terminal 

 facets is 2 mm. Along the proximal part of the main food-grooves- 

 5 facets occur in a length of 10 mm. No clearly defined lateral grooves 

 and facets were noticed along the upper side of these main food-grooves. 



Surface ornamentation. — Two specimens of Gomphocystites from the 

 Chicago area, numbered 22943 at Chicago University, present impres- 

 sions of parts of the exterior surface. One of these consists of the 

 impression of the top of a specimen, and shows food-grooves, a relatively 

 coarsely papillate surface, and numerous diplopores, the pores of each 

 pair averaging about half a millimeter or less apart. The second spec- 

 imen retains the impression of the attenuate basal stipe, 15 mm. long, 

 and also the impression of part of the lateral wall of the globose part of 

 the theca. The tips of the food-grooves evidently reach the lower 

 slopes of the globose part of the theca. The striking feature of this 

 specimen is its strongly papillate ornamentation, the papillae on the 

 upper surface of the theca frequently being 1.5 to 2 mm. apart, while 

 those on the stipe may be one millimeter or even less distant from 

 each other. 



Food-groove system. — The food-grooves are deeply incised into the 

 outer surface of the theca. Three primary branches leave the oral 

 aperture. Of these, the anterior branch remains undivided; the right 

 branch divides slightly over one millimeter from the center of the cral 

 aperture; the left branch divides at a distance of about 2 mm., the 

 resulting total being 5 branches. The width of the food-grooves is cne 

 millimeter or less. 



Variation in the form of the theca. — Two of the specimens from the 

 Chicago area, numbered 22944 at Chicago University, namely B and C, 

 are nearly globular rather than depressed globular in form, but present 

 the same rows of laterally compressed small plates along the lower side 

 of the food-grooves as in Gomphocystites bownockeri. Specimen 22945 

 (Plate I, Figs. 9 A, B) from the same area, differs merely in its more 

 elongate form. In all of these specimens the tips cf the feed-grooves, 

 extend practically to the bas^ cf the more globular part of the theca. 



