BATOCRINIDiE. 507 



wliole calyx, a peculiar and unique character. Posterior oral strongly 

 nodose, and almost as large as the four others together; it occupies a slant- 

 ing position, leaning over to the anterior side, where it occupies a lower level 

 than at the posterior side. The smaller orals and radial dome plates highly 

 convex, about twice as large as the intervening perisomic plates. Interam- 

 bulacral pieces seven to nine to each side, slightly convex. The column, 

 which has been observed to the length of nearly eighteen inches, retains the 

 same width to the end. The nodal joints throughout are considerably wider 

 and longer than the intervening ones, and at about 10 cm. from the calyx 

 the internodes have increased to six joints, which is probably the largest 

 number in this species. Farther down on the stem, larger and smaller joints 

 alternate with one another. 



Horizon and Locality. — Upper Burlington limestone, Burlington and 

 Pleasant Grove, Iowa. 



Type in the White collection at Ann Arbor, Mich. 



Remarks. — This species is readily distinguished by the peculiar construc- 

 tion of the anal area, the asymmetry of the calyx, and the flatness of the 

 dorsal cup. 



Agaricocrinus bellatrema, var. major W. and Sp. (nov. var.). 

 Plate XLI. Fig. 5. 



This form differs from the typical A. heUatrema in the size and form of 

 the calyx, which is larger and depressed-sphasroidal in place of subpyramidal, 

 the dorsal cup being slightly more convex, and the ventral disk shorter. As 

 a rule, the plates of both hemispheres are more tumid, but especially those 

 of the ventral disk, which throughout are sharply nodose, the interambu- 

 lacral pieces as well as the others; and all plates, excepting the posterior 

 oral, are of about uniform size. The plates of the dorsal cup are but very 

 slightly convex. The construction of the anal area is the same as in the 

 typical form. 



Horizon and Locality. — Same as last. 



Described from three specimens in the collection of Wachsmuth and 

 Springer. 



