26 Trans. Acad. Set. of St. Louis. 



a number of elliptical Blastoideans which have hitherto been 

 grouped with Pentremites and Elaeacrinus. The Granaio- 

 crinus (^Pentatrematites) granulatus, Hoeuier = Granato- 

 crinus cidariformis, Troost, may be regarded as the type of 

 the genus, and for the present it may be extended so as to 

 include such species as Pentremites melo and Peritremites 

 norwoodi, Owen and Shumard, and allied forms, though it 

 may become necessary after a while to remove these from 

 Granatocrinus and group them in a separate subsection under 

 another name. They differ from Elaeacrinus in having 

 elongate radial plates, extending, in some instances, almost 

 the entire length of the pseudambulacral fields, while the 

 interradials are in most instances extremely short. The 

 structure of the summit is also quite different ; the anal 

 field is not flattened and conspicuously wider than the others, 

 and it is not provided with a supplementary lanceolate piece as 

 we find in Elaeacrinus proper." 



In the same year, 1866, F. B. Meek and Prof. Worthen 

 give us a description of the genus Granatocrinus,* which is 

 as follows : — 



" The generic formula of this group is exactly the same as 

 that of Pentremites, Say, so far as regards the number and 

 arrangement of the pieces forming the body, though the form 

 and proportions of these pieces are so different as to give a 

 very different outline and general physiognomy to the entire 

 fossil. They are therefore readily distinguished from Say's 

 genus, as properly restricted, by their regular oval, elliptical, 

 or subglobose form, concave or less protuberant base, and 

 much narrower and more elongated pseudo-ambulacral areas, 

 which extend the entire length of the body, so as to give it 

 more the appearance of an Echinoid. They likewise present 

 differences in the arrangement of the ovarian ? openings of the 

 summit, which are more intimately connected with the inter- 

 radial pieces, being sometimes excavated, one into each lateral 

 margin of these pieces (^G. sayi); or in other instances 

 piercing directly through them, so that each pair appears 



* Meek and Worthea. Geological Survey of Illinois, Vol. II., p. 274. 



