358 HYALONEMA (PHIALONEMA) BREVANCORA. 



The small micramphidiscs (Plate 89, figs. 20-30, 34) are 17.5-52 fi long, 

 most frequently about 32.5 n. The shaft is 0.8-2 n thick, and thickened in the 

 middle-part to a central tyle 2-3.3 yu in transverse diameter, that is 0.5-1.3 n 

 more than the adjacent parts of the shaft. In most of the larger and some 

 of the smaller forms the shaft is spined. In most of the small and a few of the 

 larger it is smooth. The terminal anchors are 5-20 fi long and 5.5-15 m broad. 

 The proportion of anchor-length to anchor-breadth is 100 : 75 to 100 : 110, 

 on an average 100 : 90. The proportion of the anchor-length to the total length 

 of the spicule is 1 to 2.5-4.5, on an average 1 : 3. 1 . The anchor-teeth are strongly 

 curved in their proximal and nearly straight in their distal part. Their straight 

 distal parts are slightly divergent, or nearly parallel to the shaft. 



The nearest allies of this sponge are Hyalonema (Oonema) henshawi, H. (0.) 

 densum, and H. (0.) crassipinulum. From all of them it differs by its super- 

 ficial pinules attaining a much larger size; H. (0.) densum is further distinguished 

 from it by having slightly curved microhexactine rays; H. (0.) henshawi by 

 apparently being destitute of the large macramphidiscs; and H. (0.) crassi- 

 -pinulum by having smaller spicules, by being destitute of the smaller small 

 macramphidiscs with numerous anchor-teeth, and by possessing small narrow- 

 anchored macramphidiscs and pinules with large, strongly divergent spines on 

 the proximal part of the distal ray. 



PHIALONEMA, subgen. nov. 



Species of Hyalonema, whose amphidiscs of one kind (the largest) have 

 small, very short, and relatively broad terminal anchors. 



The collection contains four specimens and two fragments of this sub- 

 genus. These belong to two species, one of which is new. 



Hyalonema (Phialonema) brevancora, sp. nov. 

 Plate 55, figs. 1-37. 



There are in the collection two fragments of this species, both from the 

 Central Tropical Pacific, Station 3684 (A.A. 17), on 10 September, 1899; 0° 50' 

 N., 137° 54' W.; depth 4504 m. (2463 f.); they grew on a bottom of light 

 yellow-gray Globigerina ooze. 



The large macramphidiscs have small, particularly low terminal anchors. 

 To this the name refers. 



