82 PROCEEDINGS OF THE NATIONAL MUSEUM vol.81 



Microdiscohexasters (fig. 9, m, 71) are of two kinds, namely, the 

 larger, which usually occurs in the hypodermal region, and the 

 smaller, which is found commonly everywhere, in the endosome, 

 ectosome, and choanosome. The larger one measures 50/x to 56/* in 

 diameter and is frequently somewhat better supplied with terminals 

 (8 to 12) than the smaller. Terminals measure 16/^ to 20/x long, 

 are generally slightly curved inward distally, and are nearly uni- 

 formly thick throughout. The terminal disks are small and are 

 furnished with minute marginal teeth. The principals are per- 

 ceptibly broad and form a cross 10/a to 12/a in axial length. The 

 common, smaller microdiscohexaster is comparatively small, meas- 

 uring 32/A to 40/i in diameter. It is a very delicate form and usually 

 occurs everywhere, except on the ectodermal region. In some places 

 in the basal region of the entire stock it is more abundant than 

 elsewhere. The principals are slender and form a cross 8/1, to 10/i 

 in axial length. Their outer end shows a disklike expansion from 

 which slender terminals arise, 12/x, to 16/* in length. 



I have always found the basidictyonal plate to be fairly thick 

 and very uneven. The irregularly contoured beams are sparsely 

 microtubercled. The meshes are very small and roundish, oval, or 

 irregular in shape. 



AULOSACCUS SCHULZEI Ijima 



Aulosaccus sclmlzei Ijima, Zool. Anz., 188G, p. 252 ; Aimot. Zool. Japou., vol. 2, 

 p. 51, 1898 ; Journ. Sci. Coll. Imp. Univ. Tokyo, vol. 18, art. 7, pp. 110-117, 

 pi. 8, figs. 26-28, pi. 9, figs. 1-12, 1904. 



A single fairly large specimen of A. schulzei was collected south- 

 east of Shimushir Island, Kuriles, at a depth of 229 fathoms (Sta- 

 tion 4803). It is exquisitely vasiform, and 87 mm broad at the 

 lower end. The greatest breadth is about 57 mm. Above the broad- 

 est part of the body the wall curves in more or less to terminate in 

 the thin oscular margin, which in this specimen is much injured. 

 The osculum is irregularly circular, with a diameter of approxi- 

 mately 34 mm. The thickness of the wall in the middle of the upper 

 half of the sponge is 5 mm ; in the middle of the lower half, about 

 18 mm. The greater part of the dermal skeleton has fallen off ; the 

 parenchymal mass exposed by abrasion presents a curly appearance. 

 The gastral surface is quite well preserved, but most of the delicate 

 endosomal skeleton has also fallen off. 



The normal oxyhexaster, which is absent in the type specimens, 

 appears intermingled wnth the hemihexactinic and hexactinic forms. 

 It measures 135/* in diameter and its center is swollen to form a 

 globular node. The terminals, generally two or occasionally three 

 in number, arising from each principal are slender and rough. 

 They seem to be rather brittle near the base, as their fragments are 

 found in abundance in the soft parts. 



