KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 



25. NIO 2. 145 



many speciraens, either in sections or on weathered surfaces, is due no doubt to the petri- 

 fying processes which have often obliterated all trace of such structure when we knoAV 

 verv well that it originally existed. 



Of the Stem onlv 12 mm. are preserved, in but one specimen. Here the diameter 

 is 8 mm., but increasing slightlv proximally. The height of the ossicles is 4 mm. (fig. 234). 



Notes on Angelins figures: 



Tab. XX, tig. 4. There is no stem in the specimen, and the IBB are much higher. 

 The ventral sac is not so perfeet. The slope of the sides of the cup is steeper. 



Tab. XX, tig. 7. The 1. post. ray is restored, together with a part of the sac on 

 that side. There are but three primibrachs in r. post. arm. Othenvise the figure is fair. 



Locality: Follingbo (f). Not known out of Gotland. 



Cyathocrinus cfr. longimanus. 



(Plate VII, figs. 243—247.) 



There are some finely preserved arms, in general appearance like those of the pre- 

 ceding species, but so far differing from them that it seems as well to keep the specimen 

 separate. Since, however, it is not known what kind of calyx and stem pertained to these 

 arms, it would be inadvisable to erect a new species. 



The brachials are rounded, but not exactly moniliform; in section they are higher 

 than wide, with a deep U-shaped ventral groove (fig. 247). The axial canal is separate. 

 The ossicles show no trace of ornament. 



The covering-plates show two main types of structure. In the first, they are coni- 

 cal and regularlv alten lating. Each plate, however, consists of three elements: a large 

 proximal piece, c 1 , a much smaller median piece, c 2 , and a minute distal piece, c 3 (fig. 

 2 4 (i ) . The median pieces, r 2 , form an almost regular row down the middle line of the 

 ventral snrface. The second tvpe of structure (fig. 24">) is a specialisation of the tirst: 

 r 3 appears to be absent; c 2 is much smaller, and, instead of carrying on the conical outline 

 of r\ forms only a. little projection on its distal margin. Thus the r's of opposite sides 

 meet one anotlier by their corners, while the c 2 s do not touch one another. Occasionallv 

 too there appear to have been minute pieces intercalated between the proximal ends of 

 the covering-plates (/). When the ventral surface of the arm is viewed directly from 

 above, a considerable portion of the brachials can be seen on either side of the covering- 

 plates. The number of covering-plates to a brachial is 37 2 — 4. The covering-plates are 

 quite smooth. 



In some respects this form may be thought to resemble C. acinotubus; but the 

 covering-plates are by no means so massive when compared with the brachials as they 

 are in that species. On the contrarv, in the number and size of its covering-plates, this 

 form approaches C. longimanus. The differences in the arrangement of the various ele- 

 ments are perhaps of no great consequence; for, not onlv do we detect variation within 



K. Sv. Vet. Akad. Handl. Band. 25. N:o 2. 19 



