BATOCRINID &. 515 : 
HABROCRINUS Angelin. 
Subgenus ACACOCRINUS W. and Sp. 
("Axaxos simple, xpivov a lily.) 
Calyx short, cyathiform. Basals three, equal. Radials rather large. 
Costals two. The distichals giving off the arms, which remain simple, and 
are composed of cuneate pieces alternately arranged, interlocking or not. 
Interbrachials in contact with the interambulacrals. Anal side wide, com- 
posed of numerous plates arranged in longitudinal rows, of which there are 
generally three. Interdistichals not observed. Structure of ventral disk 
and form of anus not known. Column round and large. 
Distribution. — Only known from the Niagara group of Indiana. 
Type. — Acacocrinus Elrodt. 
Remarks. —We attempted at first to place the following two species 
under Carpocrinus, but were unable to do so. Joh. Miller proposed this 
genus for “die mit den Actinocrinus bisher vereinigten Crinoideen, denen 
auch das unregelmiissige inferradiale aller wahren Crinoideen fehlt.” His 
definition does not apply to Carpocrinus sinyplex, Miiller’s type, if. Angelin’s 
and Zittel’s identifications are correct, for it has, according to their state- 
ments, an anal plate interposed between the radials. This, it seems to us, dis- 
qualifies Miiller’s name from further use, and it will have to be replaced by 
Habrocrinus Angelin. But from this, and from the subgenus Desmidocrinis, 
our form differs, at least the typical species, in having cuneate interlocking 
pg Ni 
arm pieces in place of transverse single joints in Habrocrinus, which we think 
is sufficient to separate the two forms subgenerically, as all other species of 
Habrocrinus have rectangular arm plates. 
Acacorinus Elrodi* W. and Sp. (nov. spec.). 
Plate XX XIV. Fig. 16. 
A small species, not over 24 mm. from the top of the stem to the top of | | 
the arms. The plates of the dorsal cup a little convex and smooth; the : 
median line of the costals and distichals slightly angular. Basals forming a 
rather large obconical cup, truncated at the end. Radials very large, as 
long as wide or a little longer, larger than the two costals together, the 
upper face concave. Costals wider than long; the second smaller than the 
* Named in honor of Dr. Moses N. Elrod, one of the pioneer geologists of Indiana, who collected the 
only known specimen. 
