172 F. A. BATHEB, CEINOIDEA OF GOTLAND. 



The covering-plates, whieh rim about 3 to a brachial, are composed of the three 

 elements usual in this genus. Internal pieces are also present (tigs. 357, 358, 365 — 368). 



II)i- 4, or sometimes 5. Their height is 1 mm., their width about 2.25 mm. Their 

 backs are rounded. The width increases slightly distalward, thus producing an imbricated 

 appearance, which is more marked in some specimens than in others. IBr x is usually orna- 

 mented with transverse rows of granules, and on highly ornamented specimens there is 

 a tendency to the same ornament on succeeding primibrachs, especially at the sides; in 

 other cases the IBr are quite smooth (tig-. 374). 



IIBr 4, sometimes 5, rarely 6. They are less wide, both proportionally and ab- 

 solutely, than IBr. They are imbricate, but not granulate. 



IIIBr 5 on the outer side of the dichotom, and 9 or 10 on the inner side. They 

 are narrower, both proportionally and absolutely, but as seen from the back are still a little 

 wider than high. 



IVBr, number uncertain. They and VBr are about as high as wide. 



Anal structures: x is hexagonal, and ornamented like the rest of the cup. It 

 supports the usual three plates, but as these are also ornamented it is not easy to discern 

 their outlines. 



The Ventral Sac extends to at least the length of the arms, and was very probably 

 longer. It is compressed dorso-ventrally, and has a thin wide lumen. It is straight or 

 gently curved and of normal Gissocrinus type. It is composed of 8 or 9 longitudinal 

 rows of plates arranged in horizontal circlets. The plates are wider than high; they have 

 a transverse fold at half their heights, and middle parts slightly raised and forming vertical 

 ridges. In a specimen otherwise highly ornamented the granulation appears to be carried 

 up the tube and induces an imbricated appearance (figs. 356, 361, 369, 370, 373, 

 374, 378). 



The Tegmen is not seen. 



The Stem is preserved in three specimens to lengths of 22 mm., 22 mm. and 31 

 mm. respeetively. It was probably about 40 mm. long. The diameters of a crushed stem 

 are 3 mm. and 2 mm. The ossicles are about 3 mm. high, alternating in size; everv 

 other one has a projecting moniliform ring of very delicate and beautiful appearance; 

 every 4th ossicle is larger than the 2nd. The articular surface is radiately striate. The 

 axial canal is quinquelobate, and has a diameter of 75 mm. In an uncrushed specimen 

 the diameter of the stem close to the crown is 3.25 mm. (tigs. 355, 361, 371, 372, 

 373, 375). 



One of the specimens (fig. 377) is small and presumably young. Its plates are 

 almost smooth. The cup is seen from below. The I BB are not quite fused in the left 

 anterior and anterior radii; 1. post. IB is distinct and large; r. post. IB is small; r. ant. 

 IB is absent and its place taken by the lower part of r. ant. B. There are very faint 

 traces of granules following the outlines of BB and RR. The proportions of the cup- 

 plates are apparently the same as in other specimens of the speeies. The arms seem tiner 

 in proportion, this is partly because they have many ossicles in the different series, ri:., 

 IBr 5 and IIBr 5 and 6, but also because the ossicles are somewhat higher in proportion. 



