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: — 



The aboA'e 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) pinuUfusutn (p. 284). From this it 

 differs by the shape of the macramphidiscs and particularly by the pinnies; 

 in H. (P.) agujanum the distal rays of the largest pinnies (together with the 

 spines) are rather slender and more or less cylindrical, in H. (P.) pinulifusu?Ji 

 they are very stout and spindle-shaped. 



