Belemnocrinus, and description of two new species. 259 



Arms comparatively robust, tapering rather rapidly to the 

 ps. The arm joints are at their surface angularly elevated in 

 middle, depressed toward the sides,- the sutures between 

 liddle angular part of each joint a strong 

 B, a peculiarity which is also observable in 

 The arms in this feature recall the charac- 

 of those of Taxocrinus and Forb^i"crinns. 

 Throughout the greater portion of the arms, every alternate 

 joint is a syzigium, very obtusely pentagonal, twice 'as large as 

 the other arm joints, and to the longer margin of each which is 

 slightly angular, is attached a pinnule. The pinnules originate 

 on a very distinct articulating scar near the upper part of the 

 plate. The intermediate plates are quadrangular in outline. 

 From the bifuricating radial to the second pinnule two quadran- 

 gular joints are interposed between those to which the pinnules 

 are attached. The great size of the syzygial joints, as compared 

 with the others, and their rather pentagonal shape, cause the 

 pinnules to branch from the arms at a considerable angle, and 

 also give to the arms a marked waving form. The pinnules 

 spring alternately from every second syzygial joint on either 

 side of the arms, they are simple, composed of quadrangular 

 joints, heavy, long, tapering but slightly, nearly all thus 

 ing the same size throughout their entire length. 



The ventral sides of the arms and pinnules are in our speci- 

 men perfectly covered with alternating minute plates. The 

 same arrangement of plates has been observed by us arching 

 the ventral furrow in the arms of Cyathoar 



inns, and Messrs. Meek and Wor- 

 then have observed it in the arms of Batocrinus. We are led 

 to believe that the ventral furrow was similarly arched in all 

 Paleozoic Crinoids. 



The anal side and proboscis 

 cannot be described. The su; 

 indistinctly carinated. 



B. Pourtalesi can be readily distinguished from any other 

 known species. From B.fiorifer, 'most -nearly 



resembles, it differs in its more globose basal cup, its smaller 

 first radials and its wider free radials, which are tally twice as 

 wide in that species, also in the proportionally shorter and 

 heavier brachial pieces, the extreme size of 1 

 as compared with the intermediate ones, tic 



ma, in the angular form of the arm joints the curving 

 sutures between them, and in the peculiar shape and ere 

 upper part of the calyx of that species. From B. 

 differs in its shorter, more globose and smaller cup and in the 

 form of the first radials. From B. typus in the same respects, 

 and also in the waving form and angular surface of the arms. 



