204 The Ohio Journal of Science [Vol. XVII, No. 6, 



Compartively little is known regarding the genus Holo- 

 cystites at present. If Holocystites cylindriciis, Hall (Log. cit. 

 PI. 12, Fig. 4) be regarded as the type of the genus, then only 

 the six specimens figured by Hall under the terms Holocystites 

 cylindricus, H. abnormis, and H. alternatus are congeneric 

 among described forms referred to this genus. The material 

 at hand is not sufficient to determine whether these six spec- 

 imens are to be referred to only three species, as done by Hall, 

 or whether they represent six distinct species. 



The type of Holocystites cylindricus (Loc. cit., PI. 12, Fig. 4) 

 is labelled as obtained by Dr. Daniel, near Grafton, Wisconsin. 

 It retains seven horizontal rows of plates, with eight plates in 

 each row. At the base, there is a trace of an eighth row, and 

 there may have been more. The oral and anal apertures are 

 not preserved. The surface of the plates probably was orna- 

 mented by low, broad pustules. The more or less radiating, 

 short, hnear markings figured by Hall probably represent short 

 horizontal pores immediately beneath the epithecal layer of the 

 plates. The interior of the plates may have been traversed by 

 numerous, coarse, vertical pores. 



In the second specimen figured by Hall under the term 

 Holocystites cylindricus (Fig. 5) the number of plates in the 

 horizontal rows is uncertain. The oral aperture is six milli- 

 meters in diameter and was either circular or subpentagonal in 

 form. At a distance of two millimeters from this aperture, on 

 the side opposite to that figured by Hall, is the anal aperture, 

 circular in form, and almost five millimeters in diameter. This 

 anal aperture is located in the lower part of the uppermost row 

 of those plates which are distinctly outlined, but the possibil- 

 ity of a row of very short plates immediately surrounding the 

 oral aperture can not be disproved. This, and the following 

 specimens, are from Racine, Wisconsin. 



In the third specimen figured by Hall under Holocystites 

 cylindricus (Loc. cit. PI. 12, Fig. 6; PI. 12a, Fig. 8) there are 

 eight horizontal rows of distinct plates, with a possibility of a 

 ninth, circum-oral row, consisting of very short plates. Neither 

 the oral nor anal aperture is distinctly indicated. The surface 

 of the plates is covered by low, broad pustules. The segments 

 of the column are only indistinctly indicated. 



{To be continued.) 



