1881.] NATURAL SCIENCES OP PHILADELPHIA. 227 



for tliey are pinnules of higher branches in the body, and hence 

 were less deeply enclosed in the test. 



It would be interesting to trace the pores in genera like Glypto- 

 crinus, in which the fixed pinnules retain their forms after they 

 became fixed ; but in those genera the arms are unfortunately 

 located at the edge of the ventral disk, and an examination is diflR- 

 cult. In all carboniferous Crinoids in which the pores are clearly 

 seen, no fixed pinnules can be traced externally in the test, and 

 apparently no free pinnules were attached to the pores, or they 

 should have been found preserved in some of our specimens. 



The proximal pinnules in the recent Crinoids contain the genital 

 glands, and it is at least not impossible that the pores as rudi- 

 mentary pinnules, served as genital organs. Tliis supposition is 

 strengthened by a comparison with the ovarian openings of the 

 Ophiiiridffi and Astrophytidse, which apparently occupy' a very 

 similar position to the pores of the Actinocrinidae. Those, we 

 believe, are said to be in part respiratory and so it is possible that 

 the pores of these Crinoids had both functions. 



As a convenient summing up of our discussion of the Sphaeroido- 

 crinidaj, we give the following 



Condensed Family Diagnosis. 



Body comparatively lar'ge, globular, conical or hiturhinate; plates 

 solidly cemented together, immovable, separated only by sutures ; 

 symmetry bilateral, sometimes almost pe?'fectly pentahedral. 



Calyx composed of basals, radials, inferradials and sometimes 

 interaxillary plates. Underbasals present or absent. Radials in 

 at least two orders, the upper one frequently extended into free 

 rays. Posterior or anal area loider than the four interradial 

 areas, and the arrangement of its plates generally distinct. 

 Ventral disk more or less elevated, constructed of numerous plates 

 forming a free arch, unsupported by oral plates. The plates of 

 the vault are arranged substantially upon the same plan as those 

 of the calyx, and consist of the same elements. Apical dome plates 

 %i'ell defined. Anus inform of a simple opening directly through 

 the vault, or prolonged into a solid tube, perforated at the distal 

 end, but loithout respiratory pores. 



Arms composed of one or two series of 2'>i€ces. Pinnules long, 

 slender, generally in contact laterally. Food grooves and ambu- 



