BATOCRINID^. 441 



Lobocrinus sequibrachiatus var. asteriscus (Meek and Wokthen). 

 Plate XXIX. Figs. 9a, b. 



I860. Actinocrinus asteriscus — Meek and Wokthen ; Proc. Acad. Nat. Sci. Pliila., p. 385. 



1866. Actiitocrinus asteriscus — Meek aad Wokihes; Geol. Rep. Illinois, Vol. II., p. 207, Plate 15, Figs. 



%a, b, c. 

 1873. Batocrinus asteriscus — Meek and Worthen ; Ibid., Vol. V., p. 308. 

 1881. Syn. of Batocrinus leqiiibracliiatus — "W. and Sp. ; Revision PalBeocr., Part II., p. 165. 



Syn. Actimcriiius aquihrachiatus, var. alatus Hall ; Boston Journ. Nat. Hist., p. 263, Photogr. 



Plate 3ff, Pigs. 21-23; and Wliitfield ; Amer. Mus. Nat. Hist., 1893, Vol. I., p. 11, Plate 1, 



Pig. 14. 



This variety differs from the typical Lobocrinus cequihracliiatus in the short- 

 ness of the calyx, the flatness of the ventral disk, in being more deeply 

 lobed at the arm bases, in the larger size of the costals, and in the con- 

 dition of the interbrachial and interambulacral plates, which are in contact 

 at all sides. 



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



Type in the (Worthen) Illinois State collection, Springfield. 



Lobocrinus Yandelli (Shumaed). 

 Plate XXX: Figs. 7a, h. 



1857. Actinocrinus Tandelli — SsnMAED ; Trans. St. Louis Acad. Sci., Vol. I., p. 76, Plate 1, Figs. 



4a, 3, c, 

 1873. Actimcriiius Tandelli — Meek and Wokthen; Geol. Rep. Illinois, Vol. V., p. 341. 

 1831. Batocrinus Tandelli — W. and Sp. ; Revision Paleeocr., Part II., p. 168. 



A large, very knobby and rugose species. Calyx depressed ; the ventral 

 disk from one fourth to one third higher than the dorsal cup, the latter ab- 

 ruptly spreading from the top of the basals to the bases of the free arms, form- 

 ing a low cup or basin, which is followed by a conical disk. The interradial 

 spaces are deeply depressed between the rays at the arm bases, especially the 

 posterior one which also is wider. The surface of the plates is covered by 

 prominent knobs, either transversely or longitudinally arranged. 



Base short, truncated at the bottom ; the lower margins projecting out- 

 wards and considerably thickened ; the upper faces deeply emarginated 

 toward the sutures, and the suture lines distinctly grooved, giving to the 

 base, as seen from below, a decidedly trilobate aspect. The column facet 

 occupies one half the width of the base, and is slightly impressed, its sur- 

 face crenulated at the margin. Radials twice as wide as long ; their upper 

 faces a little concave ; the upper sloping faces rather short. The plates 



