BRYOZOA. 513 



in width from 12 to 32 mm. The surface of the cups slopes 

 gradually up to the base of the sharp edged ridges. At the 

 bottom there is usually a long and narrow depressed macula 

 or ''dimple," and on each side arranged in a more or less dis- 

 tinctly pinnate manner, are a series of long, curving, sharply 

 depressed, parallel dimples, about 1.2 mm. wide, and from 7 to 

 16 mm. long. 



The ridges on one side of the expansion correspond to the 

 central depressions on the other. Zooecia apertures very slightly 

 oblique, sub-circular or oval, 0.15 to 0.20 mm. in diameter, ar- 

 ranged in from four to eight (usually five) alternating rows 

 between the dimples, about nine in 3 mm. Peristome moderate, 

 somewhat more elevated on one side than on the other. In- 

 terspaces depressed when perfect, usually about half as wide as 

 the apertures. In thin sections the zooecial tubes have moderately 

 thick ring-like walls, a portion of the wall being distinguishable 

 from the rest as the lunariuni by its lighter color. A large 

 number of small vesicles occupy the interspaces between the 

 zooecia walls. 



The specimen originally figured by Dr. Prout was apparently 

 somewhat crushed, and scarcely shows the characteristic plu- 

 mose arrangement of the dimples. He also describes and illus- 

 trates the form here described as G. sagenella, var caliculosa, as 

 the opposite or "cupuliferous" side of G. plumosa. This is evi- 

 dently a case of faulty observation since the two sides of the 

 expansion are approximately alike. 



Position and locality: Warsaw beds. Rather rare at War- 

 saw. 111., and Barrett's Station, St. Louis Co., Mo. 



GLYPTOPOBA SAGEXELLA Prout. 



PI. LXXVin, fig. 6, 6a. 



Coscinium sogenella Prout, 1859. Trans. St. Louis Acad. Sci. vol. I, p. 573. 

 Coscinium sagenella Prout, 1866. Geol. Surv. 111. vol. H, p. 415, PI. XXII, fig. 5. 5a. 



Zoarium erect, higher than wide, the dimensions varying with 

 age, the largest seen being about eight cm. high and four cm. 

 in its greatest width. Both sides with strong sharp ridges, di- 

 viding and coalescing so as to enclose concave depressions or 



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