DE8CBIPTION8 OF THE SPECIES. 207 



bodies, Bides flat and highly inclined ; .sinuses very long, with steep Bides ; lips simple, 

 not produced or overhanging; ornament consisting of close, slightly wavy subimbri- 

 cating lines, following the outline of the plates; one or two impressed lines run 

 parallel to the margins, producing a kind of border. Ambulacra very narrow, almosl 

 linear, tapering only at the extreme outer ends, lancet-plate quite concealed; side 

 plates numerous, thirty-five and more; outer side plates tongue-shaped. Hydrospiri - 

 very small, three on each side of an ambulacrum. 



Remarks. Although Etoemer only figured isolated radials of this species he men- 

 tioned that he had seen entire examples of it in the collection of Messrs. Yandell 

 and Shumard at Louisville, and that the latter author had given it the .MS. name of 

 P. OCCidentalis. Unfortunately, however, .Shumard never authenticated this name 

 by either description or figure, and nothing is known of the rest of the calyx unless 

 the type he identical with that which was subsequently described as Tricoelocrinus 

 Woodmani by Meek and Worthen (PL XIX. figs. 13-10). But we are inclined to 

 think that this is not the case. 



Isolated radials of T. obliquatus occur in the National Collection (PI. XVI II. tigs. 

 10-13) and Prof. Boomer has kindly permitted us to examine his original types of 

 the species. In our own specimens we cannot make out more than three hydrospire- 

 folds on each side of the ambulacrum (PI. XVIII. fig 11); but in one of those 

 belonging to Prof. Boemer there seem to be indications of a larger number. 



After describing Pentremites obliquatus, Boemer pointed out 1 that the internal 

 cast found by Owen and Shumard in Randolph County, Illinois, and described by 

 them as P. latcrniformis-, " erinnert durch die verlangerte prismatische Gestalt des 

 Kelches und durch die schmalen Hnearischen Pseudambulacral-Felder an den 

 P. obliquatus, n. sp., obgleich die specifische Verschiedenheit nicht zweifelhaft ist." 

 Shumard 3 , however, expressed his belief that the cast P. laterniformis really is to be 

 referred to P. obliquatus, Boemer ; but we are inclined to doubt this, as no Trica lo- 

 crinus is known in the Chester Group either at Randolph County, Illinois, or else- 

 where ; and we think it more probable that Hambach 4 is right in referring the cast 

 to Pentremites, though not, we think, to P. sulcatus, for which it seems to us to be 

 i datively too high, as we have explained on p. 150. 



Roemer's specimens of P. obliquatus were obtained in AVashington County, Indiana, 

 and P. laterniformis, which he did not regard as identical with P. obliquatus, was 

 found by Owen and Shumard in Randolph County, Illinois. But Messrs. "Worthen 

 and Meek 5 seem to have altogether misunderstood Boemer's remarks on the suhject ; 

 for they say that P. obliquatus "also occurs in the Warsaw division of the St. Louis 



1 Archiv f. Naturgesch. 1851, Jahrg. xvii. Bd. i. p. 392. 



- Wisconsin, Iowa, and Minnesota Geol. lteport, 1S52, p. 5U2, Tab. v. tig. 15. 



3 Trans. St. Louis Acad. Sri. 1865, vol. ii. no. 2, p. 384. 



A Ibid. \-m, vol. i\. m>. 1, p 147. s Report Geol. Survey Illinois, 1875, vol. vi. p. 52L 



