132 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



Erinocystis volborthi Jaekel. 



Fig. 3. Basal view of an individual, showing the marked flattening of one side and 

 the carrying outward and backward of the anal opening. From Jaekel, 

 1899. (PI. 13, fig. 6a.) 



Pleurocystis filitextus Billings. 

 (See also Plate 3, fig. 3.) 



4. Anal (lower) side, somewhat enlarged. Adapted from Jaekel, 1899. (PI. 12, 



fig. 5.) 



Arachnoqjstis infaustus (Barrande). 



5. A specimen with the stem essentially complete. From Barrande, 1887. 



(PI. 25, fig. 7.) 



6. A portion of the column enlarged. From Barrande, 1887. (PI. 25, fig. 8.) 



Macroajstdla viarice Callaway. 



7. Reconstruction of crown and stem by Bather. From Bather, 1900. (Text 



fig. 18, p. 56.) 



Echinoencrinus angulosus (Pander). 



8. Specimen showing flattening of the lower side of the theca, the posterior loca- 



tion of the anal opening, and the nature of the column. From Jaekel, 



1899. (PI. 13, fig. 18.) 



Erinocystis angulata Jaekel. 



9. Specimen showing the extreme outward and backward location of the anal 



opening. From Jaekel, 1899. (PI. 13, fig. 16a.) 



Plate 3. 



Placocystis forbesianus de Koninck. 



Fig. 1. Convex upper (dorsal) surface of theca with a portion of the column. After 

 Bather, 1900. (Text fig. 13, 1, p. 51.) 



2. Flattened lower (ventral) sm'face showing adoral appendages ("spines"). 



After Bather, 1900. (Text fig. 13, 2, p. 51.) 



Pleurocystis filitextus Billings. 

 (See also Plate 2, fig. 4.) 



3. Specimen preserving a portion of the brachioles and an essentially complete 



column. Original in the collection of the University of Chicago. 



Trochocystis bohemicus Barrande. 



4. The terminal adoral hinged plate, approximately X 2. From Barrande, 



1887. (PI. 3, fig. 22.) 



5. A complete column of this species, approximately X 2^. From Barrande, 



1887. (PI. 3, fig. 17.) 



Mitrocystis mitra Barrande. 



6. Lower (ventral) sin-face of theca with appended column. From Bather, 



1900. (Text fig. 12, 1, p. 50.) After Barrande. 



7. Convex upper (dorsal) surface. From Bather, 1900. (Text fig. 12, 2, p. 50.) 



After Barrande. 



8. Inner surface of adoral portion of upper thecal wall, showing longitudinal 



corrugations on the central terminal plate. From Bather, 1900. (Text 

 fig. 12, 3, p. 50.) After Barrande. 



