HYALONEMA (PRIONEMA) AGUJANUM. 
265 
The spines are vertical, or inclined toward the centre of the spicule. The anchor- 
teeth arise vertically from the end of the shaft, and are uniformly curved through 
an angle of about 90°, so that their end-parts are nearly parallel. The dimensions 
of the small micramphidiscs are: — - 
var. tenuis 
var. lata 
form A 
form B 
Total 
length 
limits /u 
20-30 
18-33 
18-26.8 
most frequently 
about m 
24.5 
24.5 
20, 24.5 
Shaft, thickness n 
0.8-1. 3 
1-1.5 
Anchor 
length, limits n 
5-8.5 
4-12 
5-7.5 
breadth, limits m 
6-9.5 
6-9 
7-8.5 
Proportion of 
anchor-length to 
anchor-breadth 
limits 100: 
93-160 
75-200 
100-160 
average 100: 
122 
107 
127 
Proportion of 
anchor-length to 
total length of the 
whole spicule 
limits 1 : 
2. 9-4. 9 
2. 5-5. 9 
2. 9-4. 4 
average 1: 
3.8 
4 
3.6 
The above description shows that these sponges are similar enough to be 
considered one species. The greater average relative breadth of the serrated 
amphidiscs, particularly the larger, and some other peculiarities in one of the 
specimens, call for the recognition of two varieties: — var. tenuis with narrower 
serrated amphidisc-anchors, and var. lata with broader. One of the four speci- 
mens of var. tenuis has much smaller macramphidiscs than the others, and I 
consequently distinguish two forms in it : — A with larger, and B with smaller 
macramphidiscs. 
The nearest ally of Hyalonema ( Prionema ) agujanum appears to be the 
sponge I describe as Hyalonema ( Prionema ) pinulifusum (p. 284). From this it 
differs by the shape of the macramphidiscs and particularly by the pinules; 
in H. ( P .) agujanum the distal rays of the largest pinules (together with the 
spines) are rather slender and more or less cylindrical, in H. ( P .) pinulifusum 
they are very stout and spindle-shaped. 
