HEXACTINELLIDA. 9 
each 83 x I1p; in C autogastral pentactins (IV. 3c’) are, in addition to the hexactins, 
quite common. 
On re-examining the autogastral hexactins of A, B, C,I find the differences are not 
so great as is depicted in IV. 2c and IV. 3c. The spicule shown in IV. 2¢ has excep- 
tionally long and slender rays, and that shown in IV. 3c has exceptionally short and blunt 
rays. Inspecimen B the rays (266 x 15,) are slender, sharp-pointed and slightly spined. 
Intermedia. The holoxyhexasters, hemioxyhexasters and monoxyhexasters show 
a considerable amount of variation and abnormality, especially in the twin specimen C. 
The holoxyhexasters and hemioxyhexasters are on an average from 100 to 110p in 
diameter; fig. 3d shows a small holoxyhexaster (in optical section) only 62m in 
diameter. Usually the primary rays are small but distinct. The monoxyhexasters 
(IV. 3d**), 126 in diameter, have sharp-pointed secondary rays with rough surface, 
are broad at the base 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 
“rays to a few spines. In some hexasters (IV. 3e) the secondary rays terminate in two 
or three sharp prickles. 
3d° shows a stauractin-like monoxyhexaster, 145 in diameter, the rays having a 
roughened surface. That these spicules are not young autodermal 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 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 
trifid terminations. 
Hemidiscohexasters of medium size (IV. 3e, e'), average about 85y in diameter ; 
the rays are sometimes thicker and straighter than is usual in this species. 
Monodiscohexasters, 90” in diameter, occur rarely. Prof. Schulze figures 
(6, pl. LV., fig. 8) a spicule of this kind—the only one found by him—from a 
specimen from Kerguelen Island. 
The microdiscohexasters (IV. 3k), 50 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 5 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. 774° S., long. 175° W. ; 548 m. (300 fms.) ; Sir J. C. Ross’s Expedition. 
Prince Edward Island, 256 m. (140 fms.) ; Voy. ‘ Challenger.’ 
