NATURAL SCIENCES OF PHILADELPHIA. 349 



thought it probably had only twenty-two arms, while perfect specimens in 

 Mr. Wachsmuth's collection show that they continued bifurcating farther up, 

 so as to make the whole number about fifty-three or more, as already stated 

 in another place. 



Amongst Mr. Wachsmuth's specimens there is one (No. 13G) with arms, body, 

 vault and proboscis all in a remarkably fine state of preservation, which appears 

 to agree very closely with the A. divergensm most of its characters, and yet dif- 

 fers in several respects. It has very nearly the same number of ultimate 

 divisions in the entire series of arms, though there are differences in the 

 details of their mode of divisions, so that the number of arms in any one of 

 the rays is different from what we see in the corresponding ray of A. diver- 

 gens. In each of its posterior rays there are, as near as can be made out, 

 thirteen to fifteen arms ; in one of the lateral rays and the anterior one, each 

 eight, and the other lateral one eleven or twelve. Its ventral tube (proboscis) 

 is rather stout, about one inch in length, and crowned by some six or seven 

 small unequal spines, subspirally arranged. At the anterior side of the base 

 of the proboscis, and nearly at the centre of the vault, there is a large tumid 

 piece, and on each side of this a spine about three-fourths of an inch in length, 

 directed obliquely outward, upward and forward, and in front of these two 

 other prominent or subspiniform pieces. In the typical A. diverg(ns, these 

 two anterior lateral larger spines each bifurcate, while in the specimen 

 under consideration they are simple. The usual vermicular markings of the 

 body plates in the specimen are well defined, and on the upper anal and vault 

 pieces, as well as on those composing the proboscis, and even on the spines, the 

 whole surface of which is occupied by rather coarse granules. As in the other 

 species of this group, the arms of which are known, they extend at their bases, 

 first horizontally outward, or even a little downward, and then curve upward. 



It is probable that this specimen, with simple instead of bifurcating vault 

 spines, and somewhat differently divided arms, may be specifically distinct from 

 the A. divergens. If so, we would propose to call it Amphoracrinus multira- 

 mosus. 



Genus BATOCRINUS, Casseday. 



From deference to the most generally prevalent opinions of palaeontologists, 

 we have elsewhere included Batocrinus as a subgenus under Actinotrinvs, 

 though we did so with a protest, staling that we were strongly inclined to view 

 it as a distinct genus. Our recent study of Mr. Wachsmuth's extensive collec- 

 tions has still more decidedly impressed us with necessity for separating these 

 groups generically. 



As we have in other places stated the genus Batocrinus presents no essential 

 difference from Actinocrinus in the number and arrangement of the pieces com- 

 posing the walls of the body below the arms, nor in the vault and its elongated 

 central or subcentral tube, though its second radial pieces generally differ 

 in being proportionally shorter and quadrangular, instead of hexagonal or 

 pentagonal. One of the most obvious differences, however, consists in the 

 arrangement of the brachial pieces and adjacent parts, which in Batocrinus 

 form a nearly or quite continuous series all around, instead of being grouped 

 into five protuberant lobes, separated by more or less wide and deep interra- 

 dial and anal sinuses. Again, in Batocrinus the arms never bifurcate as we 

 often see in Actinocrinus. all the divisions of the rays taking place in the walls 

 of the body below the brachial pieces ; while the arms, (which in all cases 

 yet known, with one exception, spring singly from each arm-opening), are 

 generally much shorter in proportion to the length of the proboscis, which 

 often projects from one-third to one-half its entire length, beyond the extreme 

 ends of the arms. Another difference is to be observed in the surface of the body 

 plates, these pieces never being sculptured or ornamented with radiating costse, 

 as is often seen in Actinocrinus, but merely even, more or less tumid, or tuber- 

 culiform. The vault pieces in Batocrinus are also generally tuberculiform, or 



1868.] 



