BRITISH SPONGIAD^. 287 



I am compelled to leave the greater part of the specific 

 characters of this sponge in a state of uncertainty. 



I received the only specimen I have seen from my kind 

 friend the late Mrs. Griffith, labelled " scarlet when alive, 

 Ilfracomb." In the state in vphich I found it, it vras an 

 amorphous mass of light brown sponge an inch and a half 

 in length, one inch in breadth, and about two thirds of an 

 inch in thickness. Its substance was much intermixed 

 with small branches of Zoophytes, young shells of Mytilus 

 ■and other extraneous matter, with scarcely any appearance of 

 dermal membrane or well-defined oscula or pores ; and it 

 was only by the direction of the primary lines of the 

 network of the skeleton that I could determine with cer- 

 tainty which was the superior surface of the sponge. 



I could not detect in the few small patches of the dermal 

 membrane remaining undecomposed any appearance of 

 reticulated or irregularly imbedded spicula, and I have, 

 therefore, presumed that it is aspiculous. 



The structural character of the skeleton is somewhat 

 like that of /. anomala, but the form of the spicula of that 

 species at once separates them. The form of the spicula of 

 1. indistincta is the same as those of /. indefinita, but 

 they differ widely in their proportions, the latter being j^jth 

 inch in length and stout in proportion, while the spicula of 

 the former do not exceed ^ih. in length, and are less in 

 diameter in proportion to their diminished length, so that 

 the disparity in size will always serve to distinguish the 

 two species. 



10. IsoDicTTA PARASITICA, Bowerbunk. 



Halichondbia. pakasiiica. Johnstonian Collection, British Museum. 



Sponge. Massive, sessile, parasitical on Zoophytes, &c. 

 Surface even, smooth. Oscula and pores incon- 

 spicuous. Dermal membrane obsolete. Skeleton 

 diffuse and irregular; primary lines multispiculous, 

 flexuous, and irregular; secondary lines irregular. 



