20C CATALOGUE OF THE BLASTOIDEA. 



name by Messrs. Worth en and Meek. Figs. 10 and 11 on PI. XVIII. represent the 

 outer and inner faces of one of these radials ; and the hydrospires are seen in fig. 11 

 to disappear within the substance of the radial a long way above the point which 

 corresponds to the distal end of its ambulacrum. Fig. 13 is a sectional view of the 

 piece of a D radial shown in fig. 12 ; and the shallowness of the radial sinus, as com- 

 pared with the thickness of the plate, is well seen, as is also the very great reduction 

 in the number of hydrospire-folds. This point is also well shown in a section of a 

 smaller Triccelocrinus from the Warsaw Limestone in Mr. Wachsmuth's collection 

 (PI. XVIII. fig. 9). 



The spiracles of Triccelocrinus Woodmani, the only species in which we have seen 

 them at all satisfactorily, do not seem to be completely divided except on the anal 

 side (PI. XIX. figs. 15, 10), where they occupy the same relative position as those of 

 Metablastus lineatus (PI. 111. figs. 14, 15). 



Species. Four species of Triccelocrinus are known to us, though it is possible that 

 the first and third are identical. 



Triccelocrinus Meekianus, E. and C. Warsaw Limestone, Subcarboniferous : 



Indiana. 

 Pentremites obliquatus, Roemer. Subcarboniferous : Indiana. 

 Pentremites (Triccelocrinus) obliquatus, Worthen and Meek. Warsaw Lime- 

 stone, Subcarboniferous : Illinois. 

 Pentremites (Troostocrinus) Woodmani, Meek and Worthen. Keokuk Group ?, 



and Warsaw Limestone, Subcarboni- 

 ferous : Indiana. 

 Distribution. Triccelocrinus is thus an essentially Carboniferous type, and so far as 

 we at present know, it is limited to the Keokuk and St. Louis Groups of the Ame- 

 rican Carboniferous system. 



Type. Pentremites Woodmani, Meek and Worthen. 



Triccelocrinus obliquatus, Boemer, sp. 



(PI. XVIII. figs. 10-13.) 



Pentremites Occident alls, Shumard, MS. (fide Roemer). 



l'< iitutrematites obliquatus, Roemer, Archiv f. Naturgesch. 1851, Jahrg. xvii. p. 367, t. 6. 



f. 11. a & b. 

 Pentremites obliquatus, Dujardin and Hupe, Hist. Nat. Zooph. Ecliinod. 1802, p. 97. 

 Triccelocrinus obliquatus, E. & C, Ann. & Mag. Nat. Hist. 1883, vol. xi. p. 243. 



Sp. Char. Radial plates very thick, elongate-oblong, or in the form of an elongated 

 parallelogram with unsymmetrical ends, the marginal outline in one plane, but the 

 surface highly arched and in two planes, which cut one another at the radial lips ; 

 bodies much shorter than the limbs, strongly bent down in the direction of the basi- 

 radial sutures, limbs long, having a much less marked median inclination than the 



