the Morphology of the Blastoidea. 237 



Granatocrinus, (pars) Hall, loth Annual Eep. State Cab. N. York, 

 18(J2, p. 146; (pars) Shumard, Trans. St. Louis Acad. 1805 (.^),ii, 

 p. 375 ; (pars) Meek & Worthen, Illiuois Geol. Surve}' Report, 

 1866, ii. p. 274. 



Ohs. The mnjority of American palaeontologists have agreed 

 to distinguish as a separate genus a series of forms having 

 the general structure of Pentremites Noricoodi, O. & S., P. 

 melo, O. & S., and P. Sayi, Shumard. To these have been 

 applied the name Granatocrinus, which was first proposed by 

 the late Dr. G. Troost as Granatocrinites, the type being the 

 G. cidariformis, Troost. Neither of these ever became more 

 than a MS. name; and, according to Dr. Shumard*, the 

 species is identical with Pentremites granulatus, Romer. 

 The latter unfortunately is equally little known, having 

 been described only from an internal cast, no mention being 

 made of the summit-characters. Under these circumstances, 

 and for a due appreciation of the generic characters, we are 

 obliged to seek another type. We believe this may be most 

 readily found in Pentremites Nortcoodi, 0. & S., not only 

 from its general acceptance as a typical Granatocrinus, but 

 as one of the species first referred to this genus. 



We believe that Prof. James Hall was the first to use the 

 name Granatocrinus '\, although Avithout any precise defi- 

 nition, and after him Dr. Shumard \, who included in it a 

 larger number of species than have been retained by later 

 American writers. The first actual description of Granato- 

 crinus to appear was by Meek & Worthen §, who supplement 

 their definition by the following remarks : — " The generic 

 formula of this group is exactly the same as that of Pentre- 

 mites, Say, so iar as regards the number andar rangcment of 

 the pieces forming the body, though the form and proportions 

 of these pieces are so unlike as to give a very different out- 

 line and general physiognomy to the entire fossil. They are 

 therefore readily distinguished from Say's genus, as properly 

 restricted, by the irregular oval, elliptical, or subglobose torn], 

 concave or less protuberant base, and much narroAver and 

 more elongated jiseudo-ambulacral areas, which extend the 

 entire length of the body, so as to give it more the appear- 

 ance of an Echinoid. 'ihey likewise present difierences in 

 the arrangement of the ovarian (?) openings of the summit, 

 which are more intimately connected with the interradial 

 pieces, being sometimes excavated one into each lateral 



* Trans. St. Louis Acad. ii. p. 375. 



t lOth Annual Koport State Cab. Nat. Hist. New York, 180-^, p 146 



X Op. at. 



§ Illinois Geol. Survey Repta-t, 1806, ii. p. 274. 



