234 HYALONEMA (HYALONEMA) TYLOSTYLUM. 
The terminal anchors are 34-85 y» long, from less than a third to more than 
two fifths of the whole spicule, and 19-53 4 bread. The proportion of their 
length to their breadth is 100 to 46-88, on an average 100 : 58.3. As in the 
large macramphidises, the relative breadth of the anchors is, roughly speaking, 
in proportion to the size of the spicule. In the smaller small macramphidises, 
under 170 4 in length, the proportion of anchor-length to anchor-breadth is 
100 to 46-62, on an average 100 :55.8; in the larger, over 170 » ‘in length, 
this proportion is 100 to 48-88, on an average 100 : 60.8. 
The individual teeth are curved strongly in their basal part. Distally the 
curvature decreases, and it is on the whole such that the end-parts of the teeth 
are usually slightly convergent. 
In one of the spicule-preparations I found an amphidise with a supernu- 
merary anchor-crowned ray arising from the central tyle. The main shaft is 
110 » long and 2 4 thick. The central tyle is 4 u in diameter. The main ter- 
minal anchors are 32 uw long and 31 uw broad. The supernumerary ray is 27 pu 
long. Its terminal anchor is 18 » long and 28 » broad. The ends of adjacent 
teeth of different anchors lie in a straight line. The main shaft and the super- 
numerary ray are densely spined throughout. This spicule might be termed a 
triadise. 
The micramphidiscs (Plate 69, figs. 15-18) are 29-49 » long, most fre- 
quently about 35 » long. The shaft is straight, 0.7-1.1 » thick, and either uni- 
form in thickness, cylindrical throughout, or slightly and gradually thickened at 
or near the middle to a central tyle which is sometimes 1.3 » in diameter. The 
shaft is either quite smooth or it bears a larger or smaller number of minute 
spines. The anchors are 5-11 » long, a quarter to a fifth of the whole spicule, 
and 5-9 uw broad. The proportion of their length to their breadth is 100 to 65— 
150, on an average 100 : 88.9. The anchors of the largest micramphidiscs, that is 
those over 40 uw in length, are, on the whole, more slender than those of the 
others. The proportion of anchor-length to anchor-breadth is in these large 
micramphidises 100 to 75-87, on an average 100 : 80.8. The individual anchor- 
teeth are curved so that their end-parts are either parallel or convergent. 
The nearest allies of the sponges above described are the species Hyalonema 
(Hyalonema) placuna and H. (H.) tenwfusum described in this Report. From 
these they differ by possessing tylostyle megascleres; by being destitute of 
microhexactines with two longer opposite (apical) and four more or less reduced 
(lateral) rays; by the smaller size of the distal rays of their dermal pinules, and 
by other characters. 
