Ps 
7 
BATOCRINID&. AQT 
by a large radial plate at each bifurcation. The orals pushed anteriorly. 
Respiratory pores arranged in ten pairs, five of them placed between the 
rays, the five others between their main divisions; they are well defined, 
and occupy the margin of the ventral disk, a little to one side of the ambu- 
lacral openings. 
Listribution. — The only known species occurs in the Keokuk group of 
the Mississippi Valley. 
Remarks.— The genus Alloprosallocrinus is most remarkable for the short- 
ness of the dorsal cup contrasted with the great height of the ventral disk, in 
which it resembles Agaricocrinus. The form of the arm facets in the two 
genera is also quite similar, and they probably had the same kind of arms; 
but in Agaricocrinus the anus opens out laterally, directly through the disk, 
while in Adloprosallocrinus it is placed at the end of a tube, and besides, the 
former having two well defined costals. 
Meek and Worthen’s AWloprosallocrinus euconus is a Dizygocrinus; it resem- 
bles the former somewhat in its form, but it has two costals, the arms are 
comparatively thin, and become paired in mature specimens. 
Casseday and Lyon’s Alloprosallocrinus depressus is probably an Agarico- 
crinus ; the type specimen is too much distorted to admit a correct diagnosis. 
Alloprosallocrinus conicus Cass. and Lyon. 
Plate XLII. Figs. 14a, 6, ¢. 
1860. . Cassepay and Lyon; Proceed. Amer. Acad. of Arts and Sci., Vol. V., p. 29. 
1866. Suumarp (Subgenus of Actinocrinus); Catal. Paleeoz. Foss. (Trans. Acad. Sci. St. Louis, Vol, IT., 
1881. W. coe Revision Paleoer., Part IL, p- 114 (Proceed. Acad. Nat. Sci. Phila., p. 288). 
Alloprosaliocrinus Gurleyi 8. A. Minter; 1891, Adv. Sheets 17th Rep. Geol. Surv. Indiana, 
p- 58, Plate 10, Figs. 1 and 2. 
Calyx pyramidal; the dorsal cup so flat that it is almost invisible from 
aside view; the ventral disk high and distinctly conical. Plates thick and 
devoid of ornamentation ; those of the dorsal cup very slightly convex; the 
plates of the tegmen varying from convex to nodose. 
Basals small, forming an inverted hexagonal basin. Radials wider than 
high, the lower portions bending inward, and forming a part of the basal 
concavity. Costals generally so closely anchylosed that a suture line cannot 
be traced, both together are pentangular, a little wider than the radials, and 
wider than long. Distichals 2 X 2, except in the posterior rays, of which the 
divisions next to the anal interradius have but one, which is axillary and 
