1869.] MEEK AND WORTHEN — ON PALEOZOIC CRINOIDEA. 435 



mens of a species of this genus show that it is provided with a 

 long, sleuder, pipe-stem like ventral tube, or proboscis, apparently 

 equalling the arms in length. Also, that a double row ot minute 

 alternating marginal pieces extends up within the ambulacral 

 furrows of the arms, apparently all their length. We are not 

 aware that these characters have been hitherto noticed in any of 

 the publications on this genus. It will be seen, however, farther 

 on, that minute marginal pieces probably occupied the furrows 

 along the inner side of the arms of other types of Crinoidea, as 

 well as this. 



2. Goniasteroidocrinns, T^yon and Casseday. Some unusually 

 fine specimens of the typical species of this genus (G. tuherosus) 

 in Mr. Wachsmuth's collection, from Oawfordsviile, Ind., show 

 the slender pendent arms much more distinctly than any we had 

 before seen, and from these it seems evident that those arms are 

 stouter than we had supposed, and that there are not more than 

 five or six of them to each of the ten openings. In the specimen 

 figured by us on page 220 of the second volume of the Illinois 

 Reports, these arms were only imperfectly seen by working away, 

 with great difficulty, the hard matrix between two of the produced 

 rays of the vault, which we h ;ve termed pseudobrachial append- 

 ages, or false arms. In clearing away the matrix of this specimen, 

 we had cut just far enough to expose the edges of the arms on 

 each side of the deep ambulacral furrow, so that each of these 

 edges presents the appearance of being a separate and distinct, 

 very slender arm, composed of a single series of pieces, and without 

 any ambulacral furrow on the outer or ventral side ; whereas 

 there is a well-defined ambulacral furrow, bearing the tentacula 

 along its margins, on the outer side of the arms, and when the 

 matrix is removed from these ambulacral furrows, the arms can 

 be seen to be composed each of a double series of small alternately- 

 arranged pieces. It is barely possible that in specimens of this 

 species with the arms perfectly pieserved^ that the ambulacral 

 furrows may be covered on the outer or ventral side by a double 

 series of alternating pieces, and that the tentacula* may connect 



* "We use the term tentacula here in the sense it is generally used by 

 palgeontologists, with reference to the delicate pinnulee aloug the arms of 

 Crinoids, and of course not as applying to the minute fleshy organs along 

 the ambulacral furrows, usually termed tentacles by those whe have 

 investigated the recent Crinoids 



