58 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 81 



taper considerably toward the end, which is supplied with two or 

 three backwardly diverging, slender, short claws. Beside these 

 forms, there is a microdiscohexaster, nearly resembling that com- 

 monly occurring in the Acanthascinae and measuring 20/x in diame- 

 ter. They are scattered in the gastralia as well as in the parenchyme, 

 though much more sparsely in the latter. In parenchymal regions 

 scattered large hexactins with slender rays are rather more numer- 

 ous than in the subgastral regions. The axial length of the rays is 

 120/x, to 200//,; breadth at base, 6//,. All the six rays in the same 

 spicule in general are subequal, though in some cases the distal ray 

 is somewhat shorter than the paratangential rays. Occasionally also 

 the free proximal ray may be longer than the paratangentials. All 

 the rays are gradually tapered to the sharply pointed end. The 

 microtubercies may be slightly more pronounced on the distal ends 

 than on any other, but in any case the differentiation is never carried 

 out to any considerable degree. 



The stout oxyhexasters are present in the subdermal regions in 

 small numbers, being sparsely scattered. They measure mostly 75/x 

 to 85/1 in diameter and have remarkably thick, conic rays, measuring 

 Sfi on the base near the center of the spicules. The rays are usually 

 divided into two terminals. Occasionally they are not divided, the 

 principal being prolonged into one terminal ray. They are nearly 

 smooth over the entire surface. 



Scopulae fall into only one class, having four or six distal rays, 

 measuring 35/^ to 60/t. long, being cylindrical and covered with 

 sparse and minute tubercles, and terminating in very small round 

 enlargements. The shaft at its upper end has a definitely circum- 

 scribed enlargement on which the rays rest; tapering thence to the 

 conically shaped point, above which it is sparsely roughened. Else- 

 where it is nearly smooth. The shaft is 200/^ to 250//, over all and 

 4/1 thick just below the upper enlargement. Scopulae occur only on 

 the dermal surface, penetrating obliquely or horizontally to the 

 sponge wall, close and nearly parallel to the proximal rays of the 

 pinularlike hexactins. 



APHROCALLISTES ALEUTIANA, new species 



Several small colonies and fragments of A. aleufiana were col- 

 lected from Station 4780 (near the western extremity of the Aleutian 

 Islands). They are all nearly macerated or washed out, and can not 

 be described in any great detail. 



SpicvJation. — The dermalia are slender hexactins, with free distal 

 rays 50/i to 60/i long, terminally sometimes thickened in a nearly 

 circular pear-shaped manner. They are covered with short slender 

 thorns, which diverge slightly obliquely, and are curved toward the 

 end of the ray, showing a rounded or angularlike boss, which is 50/i 



