66 



GEODIA VARIOSPICULOSA. 



long and 0.6-2 thick at the base. In var. intermedia these asters usually have 

 from twelve to nineteen rays. Their total diameter is 5-7 p., the diameter of 

 the centrum 2-4 p.. Their rays are 0.6-2 /i long and 0.5-1.6 fi thick at the base. 

 A correlation between ray-number and spicule-size is not apparent. Occasion- 

 ally irregular tuberous structures with spiny surface, which I consider as derivates 

 of these spicules with reduced rays, have been observed. One of these, which 

 I found in var. micrasfer had the shape of a stout, short, slightly curved sausage 

 and was 9 fi long and 4 jj. broad. 



The sterrasters (Plate 19, figs. 1, 2, 11, 15-18, 31, 32) are flattened ellipsoids. 

 The proportion of length to breadth to thickness is on an average 100 : 82 : 65. 

 In the normal sterrasters the distal parts of most of the rays have a circular or 

 rather regularly polygonal transverse section, are 2-3 thick, and bear a terminal 

 verticil of usually from four to six stout lateral spines (Plate 19, figs. 1, 2). The 

 transverse sections of the distal parts of the rays which surround the umbilicus 

 are elongated in a direction radial to the centre of the latter, 2-3 /x broad, and 

 about 5 p. long. These umbilical rays bear from six to eight or more spines, 

 one of which is often (Plate 19, fig. 1) considerably larger than the others. 

 This larger spine is directed towards the centre of the umbilicus. In the centre 

 of young sterrasters, 22-26 p in diameter, of both varieties, a spherical cluster, 

 4-5 n in diameter, of numerous radially arranged, elongated, somewhat rod- 

 shaped granules, are observed. The sterrasters of var. micraster are 120 133 /x 

 long, 100 116 n broad, and 82-90 /x thick. Those of var. intermedia are 109- 

 125 /X long, 90-100 /x broad, and 70-75 /x thick. 



Besides these normal sterrasters, a few abnormal ones, similar in regard to 

 shape and size, but very different in regard to the structure of the surface, have 

 been observed. Two kinds of such sterroids can be distinguished. In one of 

 these the rays are much thicker than in the normal sterrasters. In the other 

 the rays are of the same thickness as in the normal sterrasters but destitute 

 of spines. A sterroid of the first kind is represented in Plate 19, figs. 17, 18. 

 In this sterraster the ends of the rays have more or less polygonal terminal 

 faces, 10-20 /x in diameter, densely covered with spines. A sterroid of the 

 second kind is shown in Plate 19, fig. 15, 16. 



The specimen of var. intermedia was caught with the tangles at Station 

 3746 on May 19, 1900, off Honshu Island, Japan, Suno Saki N. 87°, E. 15.8 km. 

 (8.5 miles); depth 90 m. (49 f.); it grew on a bottom of gray sand and pebbles. 

 The specimen of var. micraster was trawled at Station 3758 on May 22, 1900, 

 off Honshu Island, Japan, Suno Saki S. 55°, E. 3.9 km. (2.1 miles); depth 

 95-133 m. (73; 52 f.); it grew on a bottom of black clay and rock. 



