434 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



Horizon and Locality. — Upper Burlington limestone ; Burlington, Iowa. 



EemarJcs. — This species was described by McChesney as having but four 

 plates in the anal interradius, and three at the other sides. In that case the 

 type specimen was a very young example, in which the upper plates between 

 the rays were as yet undeveloped. 



LOBOCRINTTS W. and Sp. (nov. geu.). 

 (Ao/3ds a lobe ; npivov, a lily.) 



Form of the calyx from pyriform to wheel-shaped ; the raj^s more or 

 less distinctly lobed, and the arms arranged in groups ; the ventral disk 

 high, conical or bulging. Plates convex, smooth, or ornamented. Basals 

 three, rather large, forming a subcylindrical cup, which is thickened at the 

 lower end. Radials larger than both costals together; the second costals 

 frequently smaller than the first. Arm facets subcircular, concave, and in 

 some species provided with a transverse imperfoi-ate ridge. Arm openings 

 large, directed upward. There are no traces of respiratory pores, but they 

 may have been located close to the edges of the ambulacral ojjenings, some 

 of which are a little excavated at one side. Arms one to each opening ; 

 short, cylindrical, and biserial from the base up. Pinnules long. Inter- 

 brachials numerous, and in contact with the interambulacrals. Some species 

 have interdistichals. Anal plate succeeded by two interbrachials with a sec- 

 ond anal between them, and two or three additional rows of from two to 

 thi'ee pieces. The ventral disk is generally large, the anal tube central, 

 stout and very long. Orals well defined, being larger and more nodose than 

 the surrounding plates, especially the posterior one, which is erect, and forms 

 the base of the anal tube at the anterior side of the tegmen. The radial 

 dome plates are large and quite prominent. Column stout, round, and com- 

 paratively long ; axial canal small and pentangular. 



Distribution. — Lobocriniis, so far as known, occurs only in America, and 

 is restricted to the Burlington and Keokuk groups. 



Tijpe of the genus : Zoiocrinns Nashvillce (Troost). 



lUmarhs. — Most species of this genus wei-e originally described under 

 Adinocrinus, but were afterwards referred by Meek and Worthen to Bato- 

 cnnus, and one of them to TIperocrinus. The latter name had been proposed 

 as a subgenus of Adinocrinus with " Adinocrinus ( Uperocrimts) jiyriformis " as 

 type. By placing these species under Batocrimis, we should have to ignore 

 the principal character upon which that genus was founded, for in all of 



