346 PROCEEDINGS OP THE ACADEMY OF 



DoRYCRiNus RoEMERi, M. and W. 

 Body somewhat urn-shaped, being obconical below the arms to the truncated 

 base, and moderately prominent above, the vault forming rather more than 

 one-third of tlie entire height; greatest breadth at the arm-bases. Base trun- 

 cated and somewhat concave below, about twice as wide as high, slightly ex- 

 ])anded and a little angular below, witli broad, rather shallow notches at the 

 sutures. First radial pieces about twice and a half as wide as high, two hep- 

 tagonal and three hexagonal, each one swelling out so as to form a moderately 

 jjrominent, rather obtuse, transversely elongated node. Second radials one- 

 third to nearly one-half as long as the first, quadrangular, a little wider than 

 long, and more or less tumid. Third radials rather larger than the second, 

 wider than long, pentagonal, hexagonal and heptagonal ; each one supporting 

 on each of its superior sloping sides a pentagonal secondary radial, of rather 

 smaller size, each of which in the posterior rays supports, in its turn, on each 

 side above, one, or sometimes two, brachial pieces, making four arm-openings 

 to each of these rays. This seems to be the case also in the right lateral ray, 

 while one of the secondary radials, in the specimen studied, appears to be merely 

 truncated, so as to support (perhaps abnormally) only one brachial piece, 

 thus making only three arm-openings to this ray. The brachial and secondary 

 radial pieces of the anterior ray are broken away in the specimen, but it is 

 probable there were four arm-openings in this ray. If so, there would be nine- 

 teen arm-openings (probably normally twenty) in the entire series, and thirty- 

 eight to forty arms, counting two to each opening. 



First anal piece of the same size and form as the first radials, and, like them, 

 swelling out into a transversely elongated node. Above this there are two 

 heptagonal, and one apparently hexagonal, rather tumid pieces in the second 

 range, and above the latter several other pieces extending up between the arm- 

 bases, so as to connect with a series of pieces forming a thickened protuberance 

 rising even slightly higher than the summit of the vault, and pierced by the 

 anal opening, which is situated considerably above the horizon of the arm- 

 bases, but still directed laterally. Interradial pieces three to each area, the first 

 being about half as large as the subradials, heptagonal or octagonal, and sup- 

 porting two somewhat elongated irregularly formed pieces that are scarcely 

 convex, and connect, by their narrow upper ends, with vault pieces above. 

 Vault somewhat rounded, with lateral spines very short, or merely having the 

 form of rather prominent conical nodes; central piece somewhat tumid, but 

 not even conical. Arms and column unknown. 



Named in honor of Dr. F. Roemer, the founder of the genus Dorycrinus. 

 Height of body to top of vault, I -40 inches ; do. to top of anal protuberance, 

 1-45 inch ; breadth at arm-bases, 1-30 inch; breadth of base, fe-55 inch. 



This species is perhaps more nearly allied to D. Missouriensis, Shumard (sp ) 

 than to any other yet known. It will be readily distinguished, however, by 

 several well-marked characters. In the first place, its base is not thickened 

 and expanded as in that species. Again, its vault is not so flattened on top, 

 nor the si)ines, or tumid pieces over the rays, near so large. In the Missouri- 

 ensis the latter character is so strongly marked as to place the widest part of 

 the body above the arm-bases, which consequently have the appearance of 

 being attached half-way down the sides of the body, while in the species under 

 consideration the body is distinctly wider at the arm-base than above. Our 

 species also has seven or eight arms more than Dr. Shumard's. 



Those who prefer to view the Vorycnnus group as only a section of Actino- 

 criiiits will, vre hope, at least write the name of this species Actinocrinus i^Dory- 

 crinus') Roemeri. 



Locality and position. — Upper part of the Burlington beds, of the Lower Car- 

 boniferous series, at Burlington, Iowa. No. 127 of Mr. Wachsmuth's collection. 



DoRYCRINnS QUINQUELOBUS, Var. INTERMEDIUS. 



On comparing this form with the typical specimen of D. quinquelobus [t=Acli- 

 nocrinus quinqxielobus, Hall, Supp. Iowa Geol. Rei)ort, vol. i, p, 15), we find that 



[Dec. 



