46 



has three plates, one iu the first range and two in the second, 

 but they do not connect with the vault. The area opposite the 

 azygous area has sis plates, one in the first range, two in the 

 second and three in the third, the middle one of which is large 

 and elongated and extends over upon the vault. The other lateral 

 area has five plates, one iu the first range, two in the second and 

 two iu the third, which unite with two plates belonging to the 

 vault. 'J'here is oie ic tersecondary plate in the area to the right 

 of the azygous area, and also in the opposite area, that unites 

 with the plates of the vault. In the other intersecondary areas 

 a vault plate curves down between the arm bases and unites with 

 the secondary radials. In the azygous area there are eleven 

 plates. The first one is in line with the first primary radials and 

 quite as large. It is followed by three plates in the second range, 

 four in the third range, above which there are three plates, the 

 middle one passing up between the arm bases and uniting with 

 the plates of the vault. 



The vault is gently convex, covered with large and small pol}- 

 goual plates, and bears a subcentral azygous orifice. The arm 

 openings are directed upward. No ovarian pores discovered. 



This is a remarkable species, and will not be mistaken for any 

 other. The vault and iuterradial and intersecondary areas are 

 peculiar, but the arm structure is the most extraordinary. The 

 secondary radials that are half axillary, or bear a free arm on one 

 side and a tertiary radial on the other, is a feature of rare oc- 

 currence, but it is certainly not abnormal. Baiocrinus bisbrachia- 

 tns, Whitfield, of which we have several specimens, bears two free 

 arms on each of the last radials, without the presence of the 

 usual axillary plate, so that it is mucli farther removed from the 

 ordinary arm structure than is this species. 



Found in the Burlington Group), at liurliugton, Iowa, aud now 

 in the collection of A. Albers. 



BATOCRINUS ENODATUS, U. sp. 



Plate II, Fig. 21, (izygous side; Fig. 22, basal view; Fig. 23, 



summit. 



Species small, subglobose, viult as large as the calyx, longi- 

 tudinally constructed on the azygous side. Calyx saucer .shaped. 

 Surface of the plates plane aud smooth. 



