KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 2. 157 



iinen these latera] ridges are verv fantastically developed, and are broken up into a nuraber 

 of prickly spines (tig. 269), while the ornament on the eup seems to have been correspond- 

 iiiglv developed. The axial canal is sometimes, but not always, distinct. The ventral 

 groove is fairly b road (fig. 270). 



The covering-plates are about 5 to each brachial. Their structure is even more 

 complicated than in some of the species of Cyathocrinus previqusly described (see p. 184). 

 As seen from the ventral surface, three elements, c 1 , c 2 , c ? , may be recognised, of which 

 the first is much the largest and the third much the smallest. The c 2 s of bppo&ite sides 

 form an alternating series just above the middle line; while the c 3 of each eovering-plate 

 lies against and partlv between two 0*8 of the opposite side. Adjoining the r 3 s there may 

 occasionallv be seen a verv small intercalated plate. Although so small on the exteriör, 

 c 3 swells out below into a fairly large sized plate (tigs. 273, 275), which, together with 

 an internal intercalated plate (?'), separates <■' from the ventral groove; this plate i has 

 already been observed in Cyathocrinus. In addition to these plates, the ventral groove is 

 almost filled with some four or tive other rather large plates (tigs. 274, 275) which do 

 not conie to the exteriör. It is härd to see how the food -groove can have communicated 

 with the exteriör, imless it were at the distal ends of the arms. 



IBr 1, axillary. Height 2.75 mm., width below 2.5 mm., width altove 3.5 mm. 



IIBr 1, axillary, expanding above, longer in proportion than IBr. Usually they 

 meet above by their lateral proeesses, but rarelv they lie closely side by side as though 

 attached by suturc: there was, however, no organic connection. 



II IBr from 1 to 3, sometimes 4? 



IVBr from 2 to 7. In both III and IV Br the inner branches of the dichotom have 

 more ossicles, and their ossicles are also higher, so that the lateral proeesses do not meet. 



VBr are always present, and VIBr nearlv always; both of these have from 5 to 12 

 ossicles. VIIBr are sometimes present. 



Anal struetures: x hexagonal, supporting in the middle the proximal median 

 plate of the sac, and on either side, together with the adjacent KR, supporting the two 

 lateral plates (tig. 276). 



There is some slight variation in the precise shapes and relations of the lower plates 

 of the Ventral Sac; but they are speedilv developed into parallel series of almost qua- 

 drangular plates, which tend to lie side by side rather than to alternate (tigs. 276, 277, 

 280). The plates are wider than high, and the width increases in the distal region of the 

 tube. At the same ti me there arises on each plate a strong transverse ridge at half the 

 height of the plate, which is connected with that of the two adjacent plates. The tube 

 is about as long as the arms; it is compressed dorso-ventrallv, and has a thin wide lumen 

 (tig. 368). There appear to be 8 rows of plates. 



The Tegmen is only exposed in one specimen, and that is weathered (tig. 279). 

 It is seen to be of the same type as in Gissocrinus arthriticiCs, Phill. The ambulacra 

 are elevated, passing över the edges of 4 rather small deltoids and a madreporite. Över 

 the actinal centre are large plates which may represent covering-plates or orals. 



The Steni: in a specimen of which the Crown is 34 mm. long, the stem is 32 mm. 

 long, and has a diameter of 2.25 mm. (hg. 262). It is not quite certain that all the 



