> 



the Morphology of the Blastoidea. 243 



Practically, therefore, the hjdrospires are situated actually 

 within the substance of theradials. We have already pointed 

 out that this condition occurs at the distal ends of the ambu- 

 lacra of P. conoideus *, and that we suspect its presence in 

 Stephanocrinus, at any rate in S. angulatus, and in Astro- 

 crinus. 



We think that, apart from the other characters mentioned 

 by Meek and Worthen, this peculiarity affords an excellent 

 distinction between Triccelocrinus and Troostocrinus ; for we 

 have found the hydrospires of Troostocrinus Reinwardti and 

 T. lineatus to be perfectly normal in character, like those of 

 the typical Pentremitiche. Unfortunately we know next to 

 nothing about the spiracles of Triccelocrinus. Meek and 

 Worthen describe those of T Woodmanz as small and very 

 closely approximated ; but they say nothing about those of 

 T. obliqaatus. From various specimens that we have seen (all, 

 however, more or less incomplete) we are inclined to think 

 that the spiracles of this genus are essentially similar to those 

 of Troostocrinus. 



The following are the species comprised in the genu3 as 

 we understand it : 



\Pentremites obliquatus, Homer. Carboniferous Lime- 

 stone, Indiana. 



P. (Troostocrinus?) Woodniani 7 Meek and Worthen. 

 Keokuk group? (Lower Carboniferous), Indiana. 



P. (Tricwlocrinus) obliquatus, Meek and Worthen. St.- 

 Louis group (Lower Carboniferous), Illinois. 



8. Descriptions of three new Species from the Lower 



Devonian of Spain. 



Genus Pentremitidea, D'Orb. 1849 



(emend. E. & C. 1882). 



Pent remit idea Malladce, sp. nov. 



Sp. char. Calyx pentagono-pyramidal, expanding gradually 

 upwards, with the greatest periphery at about one third of its 

 length from the summit. Section pentagonal, with wide and 

 shallow re-entering angles between the ambulacra. Summit 



* Loc. cit. p. 216. 



t According to Komer (p. 72) there is some resemblance between the 

 linear ambulacra of this tvpe and those of the cast described by Shumard 

 as P. laterniformis. Hambach says, however, and apparently with good 

 reason, that the latter is merely an internal cast of P. sulcatus (Trans. St. 

 Louis Acad. Sci. vol. iv. p. 147, pi. B. fig. 10). 



17* 



