INVERTEBRATES. 521 



Genus PENTREMITES, Say. 

 Penteemites (Tricceloceintjs) Varsouviensis, Worthen. 



PI. 31, Fig. 8 and 9. 



Base strongly triangular, becoming pentagonal above, and a little 

 more than half as long as the radial pieces. Radials rather narrow, 

 elongate, borders nearly parallel, angulated below and flattened on 

 the sides, and truncated for the reception of the interradial pieces. 

 Interradials rather small, lanceolate, and reaching nearly or quite to 

 the summit. Pseudo-ambulacral fields narrow, linear, and extending 

 downwards less than half the length of the radial pieces, and each 

 containing about sixty pore pieces arranged in a double row. 



• This species is closely allied to P. lineatus, Shum., from the Burlington 

 limestone, but differs in its more triangular base, in the proportions of 

 its principal pieces, and in the number of pore pieces in its pseudo- 

 ambulacral fields. 



Position and locality : Warsaw, and Monroe county near Columbus, 

 Blinois, in the Warsaw division of the St. Louis group. Lower Car- 

 boniferous. 



Penteemites (Teiccelocrinus) obliquatus, Bcemer, sp. 



PI. 31, Fig. 4. 

 Pentatrcmatites obliquatus, R<esier, 1852 ; Monog. Blast., p. 47, PI. 3, fig. 11. 



This species also occurs in the Warsaw division of the St. Louis 

 group in Monroe county, Illinois, and not in the Archimedes beds of 

 Eandolph county, as cited by Rcemer. 



Genus SPIRIEER, Sowerby. 



Spieifee fastigatus, M. and W. 



PI. 30, Fig. 3. 

 Spirifer fastigatus, Meek and Wouthen, 1870. Proceed. Acad. Nat. Sci., Pkilad., p. 30. 



Shell attaining a rather large size, moderately convex, very trans- 

 verse, or distinctly more than twice as wide as long ; greatest breadth 

 on the hinge line; lateral extremities very attenuate and acutely 

 pointed in young specimens, but becoming more obtuse in larger individ- 

 uals; front and anterior lateral margins broadly and rather regularly 

 rounded. Dorsal valve nearly as convex as the ventral; beak 



