250 
PRIONEMA. 
defined central thickening can usually be made out. This is 1.2-1. 9 p in trans- 
verse diameter, that is 0.2-0. 5 \x more than the adjacent parts of the shaft. 
The anchors are 5-11 m long, one third to two fifths of the whole spicule, and 
5.5-10 m broad. The proportion of their length to their breadth is 100 to 77-129, 
on an average 100 : 107. The curvature of the anchor- teeth decreases distally, 
and their end-parts are usually fairly straight. The total curvature is such that 
the end-parts of the teeth are either parallel or slightly divergent. 
Besides the amphicliscs above described, I found an abnormal amphidisc 
with very unequal terminal anchors. This spicule is 42 p long and has a shaft 
2 [x thick. One of its anchors measures 18 p in length and 13 p in breadth, the 
other is 8 p long and broad. One half of this spicule appears as a mesamphidisc, 
the other half as a micramphidisc. 
Of the species of Hyalonema hitherto described H. divergens F. E. Schulze 1 
appears to be the one most closely allied to the sponge above described. From 
this it differs, however, to a considerable extent by the shape and dimensions of 
the spicules. The large macramphidiscs 500 p long with ovoid anchors, which 
are present in H. divergens , are absent in H. (H.) campanula. The macramphi- 
discs with campanulate anchors are small and have a strongly spined shaft and 
pointed anchor-teeth in H. divergens, and are twice as large and have, apart 
from the centrum, a nearly smooth shaft and terminally rounded anchor-teeth 
in H. ( H .) campanula. These and the other less conspicuous differences are, 
of course, cjuite sufficient for specific distinction. 
PRIONEMA, subgen. nov. 
Species of Hyalonema of which the amphidiscs of one kind have anchor-teeth 
with serrated margin. 
The collection contains twenty-one more or less complete specimens and one 
fragment of this subgenus. They belong to six species, all of which are new. 
F. E. Schulze. Rept. Voy. Challenger, 1887, 21 , p. 199, pi. 28, figs. 1-11. 
