332 HYALONEMA (OONEMA) CRASSIPINULUM. 



30 //. The proportion of anchor-length to anchor-breadth is 100 to 69-100, 

 on an average 100 : 89.5. The teeth arise nearly vertically from the ends of 

 the shaft, and are curved strongly at the base and decreasingly towards the 

 end. The tips of the teeth are usually parallel or slightly divergent. 



The small micramphidiscs (Plate 97, figs. 21-28) are 24-57 ju long, most 

 frequently about 32.4 yu. The shaft is 0.8-2 ^ thick, and generally centrotyle. 

 The central tyle is 1.8-2.6 n in transverse diameter, that is 0.3-1 ju more than 

 the adjacent parts of the shaft. Small spines are scattered over tyle and shaft 

 in the larger forms; in the smaller these spines are so minute that it is diffi- 

 cult to make them out, often they appear to be absent altogether. The anchors 

 are 7-22 fx long, usually about a third of the whole spicule. The anchor-breadth 

 is 7-19 M- The proportion of anchor-length to anchor-breadth is 100 to 71-121, 

 on an average 100 : 89.7. The teeth are sometimes remarkably numerous. 

 They arise vertically from the ends of the shaft and are more strongly curved 

 some distance from the base than proximally; beyond the strong bend, they 

 decrease in curvature, so that their end-parts are nearly straight and parallel. 

 The teeth are pointed at the end. 



The nearest allies of the above sponge are the species Hyalonema (Oonema) 

 densum, H. (0.) sequoia, and H. (0.) crassipinulum described in this Report. 

 From these it differs by being destitute of the large macramphidiscs. From 

 H. (0.) densum also it differs by having straight-rayed micramphidiscs, and 

 from the other two also by its superficial pinules being smaller and their distal 

 rays much more slender. 



Hyalonema (Oonema) crassipinulum, sp. uov. 

 Plate 92, figs. 1-23; Plate 93, figs. 1-10; Plate 94, figs. 1-33. 



One specimen of this species was trawled in the Central Pacific at Station 

 3684 (A.A. 17) on 10 September, 1899; 0° 50' N., 137° 54' W.; depth 4504 m. 

 (2463 f.) ; it grew on a bottom of light yellow-gray Globigerina ooze. 



It possesses pinules with large, remarkably divergent spines on the proximal 

 part of the distal ray. To this the name refers. 



Shape and size. The single specimen (Plate 93, fig. 9) has the shape of an 

 inverted bell, 105 mm. long, 95 mm. broad, and now strongly compressed later- 

 ally and only about 18 mm. thick. In life the sponge was probably laterally com- 

 pressed much less, or not at all. A stalk, 2.5 mm. thick and broken off rather 

 short, protrudes from the lower rounded end. The lower and lateral surfaces. 



