Z PROCEEDINGS OF THE NATIONAL MUSEUM Vol. 83 



The dorsal cup is obconical and made up of tliin plates. The infra- 

 basals form a low ring that is practically concealed by the column. 

 The basals are large, particularly the posterior, wliich is considerably 

 higher and broader than the others. The radials have a horseshoe- 

 shaped arm-facet with a width about three-fifths that of the upper 

 face of the radial. The outstanding characteristic of the arms is the 

 large number of primibrachs. The bracliials are perforated by an 

 axial canal, and the food-groove is closed by a double series of cover- 

 ing plates. There is no special anal plate, two of the tube plates rest- 

 ing directly on the upper sloping shoulders of the posterior basal. 

 The anal tube is long, slender, and composed of a few vertical series 

 of plates. The column is large, thin walled, and quadripartite and 

 may have had a multilocular structure. 



Corynecrinus is most nearly comparable to Lecythocrinus J. Miiller, 

 to which it doubtless is closely related. The dorsal cup of Coryne- 

 crinus, obconical to subcylindrical in shape, is in marked contrast to 

 the low bowl-shaped cup of Lecythocrinus. The most obvious differ- 

 ence is in arm structure, the numerous primibrachs of Corynecrinus 

 being a striking and unusual feature. The anal tube of Corynecrinus 

 is composed of relatively few ranges of comparatively large plates as 

 compared with Lecythocrinus. The column is relatively larger in 

 Corynecrinus and with a thinner wall. If a multilocular structure 

 was present the dividing partitions were much thinner. The cross 

 section of the column in Corynecrinus is subcircular rather than 

 quadrangular. 



The genotype comes from the Jeffersonville limestone (Onondaga, 

 Middle Devonian) of Clark County, Ind., and adds another form from 

 the Onondaga of North America that shows close relationships with 

 the Middle Devonian crinoid fauna of Germany. 



CORYNECRINUS ROMINGERI. new species 



The dorsal cup is obconical and as preserved is slightly compressed, 

 giving a somewhat greater breadth at the arm-bases than would be 

 normal. This is in part compensated for by a slipping and partial 

 overlap of the left anterior radial on the left posterior radial. As pre- 

 served the dorsal cup has a diameter of 6 mm at the base, 9 mm at the 

 level of the arm-bases, and a height of 7.6 mm. 



The infrabasals are small and almost completely concealed by the 

 column. It is probable that the infrabasals show on the exterior as 

 small triangular points at the lower interbasal angles and a narrow 

 band for the rest of the circuit. The sutures do not show clearly, 

 and it is difficult to differentiate between what might be an infrabasal 

 ring or the proximal columnal. The posterior basal is large relative 

 to the others, having a height of 4.8 mm as against a height of 4 mm 

 for the adjacent basal to the left. The posterior basal is heptagonal 



