HK.\A<T!NK!.UI>\. 9 



each 83 x 1 1/x ; in C uutogastral pcnbictins (IV. 3c') are, in addition to the hexactins, 

 ijuik- common. 



< tn iv-rx.-iiuiniiig the autogastral hexactins of A, B, C, I find the differences arc not 

 90 great as is ilrj.i. -ted in IV. 2 and IV. 3c. The spictilc ahmvn in IV. 2e lias excep- 

 tionallv Imii: :nnl -Iriider rays, and that shown in IV. 3c has exceptionally .short and Munt 

 rays. In sptviincii B the rays (266 x 1 5/i) are slender, sharp-pointed and slightly spined. 



Intermedia. The holoxyhexasters, hemioxyhexasters and monoxyhexastera show 

 a considerable amount of variation and abnormality, especially in the twin specimen C. 

 Tin- holoxyhexastere and hemioxyhcxasters are on an average from 100 to 110/x in 

 diiimeter ; fig. 3d shows a small holoxyhcxastcr (in optical section) only 62fi in 

 diameter. Usually the primary rays arc small hut distinct. The monoxyhcxasters 

 (IV. 3d*" 4 ), 126ft in diameter, have sharp-pointed secondary rays with rough surface, 

 are broad at the l)asc and tapering to a sharp point The abnormal spicules figured in 

 fig. 3d* have the primary rays reduced to a central node or sphere, and the secondary 



to a few spines. In some hexastcrs (IV. :Je) the secondary rays terminate in two 

 "i- three sharp prickles. 



3d* shows a stauractin-likc monoxyhcxastcr, 145/i in diameter, the rays having a 

 roughened surface. That these spicules are not young uutodcrmal .stauractins is shown 

 by the fact that the axial canals extend only a short distance from the centre. 



The calycocomes (IV. 3f-h), 80 to 90/x in diameter, show considerable variation, 

 not only in specimens B and C, but also in the same specimen, viz., variation in size, in 

 length and thickness of the primary rays, in the length and degree of divergence of the 

 secondary rays, and in the presence or absence of terminal disks. Fig. 3h, from 

 specimen B, is evidently abnormal ; here some of the secondary rays have fine bifid or 

 tritid terminations. 



Hemidiscohexasters of medium size (IV. 3e, e 1 ), average about 85/x in diameter ; 

 tln> rays are sometimes thicker and straighter than is usual in this species. 



Monodiscohexasters, 90/x in diameter, occur rarely. Prof. Schulzc figures 

 (6, pi. LV., fig. 8) a spicule of this kind the only one found by him from a 

 specimen from Kcrguelen Island. 



The microdiscohexasters (IV. 3k), 50/t in diameter, are mostly similar to those in 

 specimen A, with a narrow conical capitulum, whence two circles of secondary rays 

 originate; some, however, have a more disk-like capitulum (IV. 31); the secondary 

 rays in both kinds are extremely slender,' being almost invisible under any object-glass 

 lower than *J y inch. Curiously enough, these rays are much more easily discernible in 

 the younger and less developed specimen A. 



All from W.Q., June 3rd, 1903. No. 10 hole ; 238 m. (130 fms). 

 Other specimens have been found at : 



Lat 77$ S., long. 175 W. ; 548 m. (300 fms.) ; Sir J. C. Rosa's Expedition. 

 Prince Edward Island, 256 m. (140 fms.); Voy. 'Challenger.' 



