PALEOZOIC TIME — CARBONIC. 



641 



a foot. Pigs. 993, 994, 996, 997 are the bodies of different sjDecies of Crinoids 

 without the radiating arms. The Crinoids often have a long or short pro- 

 boscis-like projection, at the center above, which is made of stout calcareous 

 pieces like the body, but is tubular ; it is seen broken off in Figs. 993 and 

 996; and Fig. 998 represents one separate from the body of a Batocrinus 

 (near that of Fig. 996), showing the calcareous pieces constituting it. Fine 

 figures of the Subcarboniferous Crinoids, illustrating the wonderful diversity 

 of forms among them, are contained in the Illinois, Iowa, and Ohio geologi- 

 cal reports. In some species the length and form of the proboscis (which 

 contains the anal or excretory tube, not that to the mouth) are very re- 

 markable. 



Two species of Pentremites, armless bud-shaped, five-sided species, of the 

 tribe of Blastoids, eminently characteristic of the Subcarboniferous, are rep- 

 resented in Figs. 999, 1000. 



1004. 



1005. 



EcHiNorDS. — Fig-. 1004, Oligoporus nobilis (x |); 1005, Melonites multiporus, view of top (x 2). Meek and 



Worthen. 



Echinoids were of large size, and were unlike modern species in the 

 excessive number of vertical series of plates between the ambulacral areas. 

 One species (Fig. 1004) has 5 series of these plates, instead of the normal or 

 modern number, two. In Archoeocidaris (a portion of a shell of one species 

 of which is shown in Fig. 1001), the spines with which the shell was bristled 

 were (as in modern species of Cidaris) of large size and few (like Fig. 1002 

 in form), as the large prominences over the shell (Fig. 1002 a) indicate; but 

 in Fig. 1004 they were very small. Fig. 1005 is a top view, enlarged, of 

 Melonites multiporus. One very large slab in the Yale Museum, from St. 

 Louis, Mo., contains 11 Melonites to a square foot. The generic name alkides 

 to the resemblance in form to a melon. 



3. Molluscoids, — Of Molluscoids, the screw-shaped Bryozoans, species of 

 Archimedes, Fig. 1006, are characteristic. 

 Dana's manual — 41 



The screw has lost the larger 



