108 Mr. H. J. Carter on a neio Species q/'Aplysiiia 



observed to have put out several points or buds, as if about to 

 grow into a stellate (c). 



On the other hand, a ray was sometimes observed to present 

 a young branch (fig. 6, c) whose medullary or central cavity was 

 in continuation with that of the ray on which it was situated. 



Occasionally a grain of sand (fig. 4, /) was seen to be 

 attached to a horny filament after the manner of the cell, and 

 some of the stem-like filaments towards their base of attach- 

 ment had a grain or two of sand in their centre. But these 

 must be regarded as accidental occurrences ; for the structure 

 generally is not only devoid of proper spicules (that is, of 

 spicules formed by the sponge itself), but the cavity of the 

 horny fibre is equally devoid of grains of sand, fragments 

 of spicules, or any other of the minute objects which are so 

 characteristic of that in the Hirciniadse. 



The subdermal network appears to be common to most of 

 the kerataceous sponges, attaching to itself through the dermal 

 sarcode, in some of the Hircinke^ a number of minute objects, 

 so as to present a white lacework between the aculeations, 

 which is visible to the naked eye, and which, when mounted 

 in Canada balsam and viewed with a microscope, resolves 

 itself into an infinite variety of entire spicules, both siliceous 

 and calcareous, together with fragments of the same and grains 

 of sand — altogether forming a most inviting, instructive, and 

 interesting study to the spongologist. This lacework is par- 

 ticularly well developed in many of the great Hircinim at the 

 British Museum which have been collected from the West- 

 Indian seas and the coast of Southern Australia, as well as in 

 the little specimen of H. variabilis from the Adriatic Sea, 

 presented by Dr. Schmidt. In some of the kerataceous sponges 

 the network is horny, in the spiculiferous sponges spiculi- 

 ferous ; in short, more or less modified in all, it sup])orts the 

 dermal sarcode, in which the pores, in variable plurality, find 

 tliemselves conveniently placed opposite the interstices. Thus 

 the two combined form the pore-structure, which is often as 

 beautiful as it is characteristic of the species. 



I would also here add, with reference to the parasites of 

 sponges, that on one of the specimens of Aplysina corneo- 

 stellata are a number of minute isolated Ascidians attached to 

 the dermal sarcode, which, from their dark red colour, looking 

 like so many blood-red points, appear to have derived this tint 

 in some way from the colouring-matter of the Ajplysina on 

 which they were growing, as there is a portion of an Esperia 

 in the same collection, and dredged up from the same locality, 

 on which there is an equal amount of the same species of 

 Ascidians similarly situated, but without any colour at all, or, 



