136 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



a small branch horizontally at a short distance from the disk. In another 

 specimen of that species (Plate lY. Fig. 17), in which the tube is broken above 

 the arms, it was replaced by another, which starts off somewhat obliquely 

 from the top of the stump. A tube in a similar condition was observed in 

 a specimen of Lobocrinus pyriformis, but there the recuperation made but 

 little progress, for the new part did not attain one third the width of the 

 old tube at the point of fracture. In the specimen of Macrocrinus jucimdus 

 (Plate IV. Fig. 15), a small branch starts from the tube close to the calyx, 

 while in another specimen of our collection a branchlet is given off near the 

 end of the tube. In Fig. 12 of the same plate [Steganocnniis pentagomis), 

 and in Fig. 11 [Teleiocrinus umhrosiis) a second tube w\as formed at the top 

 of the disk, in the former occupying the median line of the posterior area, 

 and in the latter directed slightly to the right. In the remarkable specimen 

 of JEutrochocrinus Christyi (Wdte IV. Fig. 13) all the arms of the right pos- 

 terior YSiV, and the outer arm of both adjoining rays, w^ere destroyed, and the 

 break in the test was closed by irregular new plates, which support a con- 

 spicuous second tube. A still more remarkable instance of recuperation is 

 presented by a specimen of Batocnnus suhcequalis (Plate IV. Fig. 10), in which 

 an enormous tube breaks forth above the basals. It occupies the w^iole 

 length of the dorsal cup, and involves the plates of the posterior interradius, 

 as well as of the posterior ray, and even some of the arm openings. The 

 plates bulge outward almost at right angles to the sides of the cup, and form 

 the lower part of the tube. Fig. 9 has a very large opening between the 

 basals leaning somewhat toward the anterior side, which we think performed 

 the functions of the anus in that specimen. 



Passing now to the Inadunata Larviformia, it must be stated that, so far 

 as observed, the anal x is unrepresented throughout this group (see Figs. 4, 

 5, 6, and 19 of the preceding diagrams), and we know of no case in which the 

 anal tube, where it exists, is supported by an inferradial. This is explained 

 by the absence of interbrachial and interambulacral plates, and the position 

 of the anus intermediate between the radials and orals, or piercing the latter. 

 Fisocrinus,^ Fhimocrimis, and Symbathocrmus have a long slender tube be- 



* The tube of Pisocrinus was observed by Bather, and described by him in his late work on " The 

 Crinoidea of Gotland," Part T. p. 22). It rests npon the truncated limbs of the compound radial and the 

 large simple one to the left; but not upon the two supported by the plate W. Bather refers the proximal 

 plate of the tube to the anal x, although the plate rests, like t in Eefenocrinus and Syhocrinus, npon the 

 radials, and takes no part in the composition of the cup. So also the corresponding plate in Symhathocrinm 

 is a tube plate, and not an anal as we stated in our earlier writings. 



