24 Trims. Acad. Sci. of St. Louis. 



side conspicuously wider, more prominent, or flattened ; which 

 is the character observed in all true jSfucleocrini . 



"The different arrangement of parts, also, in the two genera, 

 causes a different mode of increase in the plates, and a differ- 

 ent surface-character. 



"There is likewise an intermediate form represented by 

 the Granatocrinus of Troost (^Pentremites granulatus ? of 

 Roemer). This species is elliptical in form, with depressed 

 base embracing in the bottom of the cavity the three small 

 basal plates, while the radial plates reach halfway up the sides 

 of the body. The anal side is not conspicuously different 

 from the others, and the summit is unlike JSFucleocrinus ; 

 while it is more nearly like Pentremites norwoodi. This 

 species is strongly granulose or tuberculose. The Pentre- 

 mites sayi appears to me to belong to the same type ; its base 

 is not depressed, leaving the three basal plates protruding; 

 while the radial plates reach about one-third the entire 

 length, in this respect approaching N'udeocrinus . In both 

 these species the plate on the anal side occupies the entire 

 space between the pseudambulacral fields, presenting scarcely 

 any important difference from the other interambulacral or 

 interradial spaces. 



' ' I would therefore suggest the separation of the species 

 under the name originally given by Dr. Troost, viz., Granato- 

 crinus . ' ' 



In 1863 Dr. Shumard's remarks regarding thegenus Elaea- 

 crinus are as follows : * — 



" There is, in my opinion, good grounds for separating from 

 the genus Pentremites those forms that have been hitherto in- 

 cluded in the group ElUptici of Prof. Roemer, and placing 

 them in the genus Elaeacrinus of the same author. We 

 therefore propose now to group in the latter genus such forms 

 as Pentreinites melo, Pentremites 7iorivoodi, P. curtus, P. 

 granidatus, P. roemeri, P. sayi, P. cor7uitus, and the species 

 we are about to describe; also the N'udeocrinus angularis of 

 Lyon. Among European species, the following may be 



* Transactions St. Louis Academy, Vol. II., p. III. 



