286 DR. J. S. BOWERBANK ON THE SPONGIADE. _[ Apr. 6, 
membrane was present as a very thin film; and the skeleton was 
indicated by a few straggling spicula only; so that in this state the 
specimen might have been readily mistaken for a Hymedesmia. 
I have named this remarkably interesting species after my good 
friend Commodore Parish, to whom I am indebted for it and many 
other interesting sponges, and also for numerous other interesting 
and valuable specimens of natural history. 
HaticHONDRIA ELEGANTIA, Bowerbank, 
Sponge massive, sessile. Surface variable but smooth, or but 
slightly rugose. Oscula simple, dispersed. Pores inconspicuous. 
Dermal membrane pellucid, in parts slightly coriaceous, furnished 
with a rather irregular unispiculous network of short acerate spicula, 
of the same form and size as those of the skeleton, and also with 
numerous simple and contort bihamate retentive spicula. Skeleton- 
rete rarely more than unispiculous, somewhat irregular; spicula 
acerate, rather short and stout. Interstitial membranes furnished 
rather abundantly with very minute simple and contort retentive 
spicula. 
Colour, in the dried state, pallid green. 
Hab. Straits of Malacca (Commodore Parish, R.N.). 
Examined in the dried state. 
I received this interesting and elegantly constructed species of 
Halichondria from my friend Commodore Parish, who obtained it 
from the Straits of Malacca. The sponge is, in a great measure, 
covered by the specimen of Microciona tuberosa described in this 
paper. Its length is about 23 inches, and its breadth about 17 inch. 
The dermal membrane is smooth and pellucid, and it is furnished 
with a beautiful unispiculous rete, the areas of which are somewhat 
unsymmetrical. The reticulated structure of the skeleton accords 
very closely with that of the dermis: it is mostly unispiculous, but 
occasionally it is bi- or trispiculous, and is characterized by the same 
irregularities in the reticulation that exist in the dermal structure, 
so that the whole structure is light and elegant. The form and size 
of the spicula are the same in all parts of the sponge; they are 
rather short and stout. The retentive spicula of the dermal and 
interstitial membranes are especially characteristic of the species ; 
they are rather abundantly distributed on some parts of those tissues 
and but sparingly so on others, and they are so minute as to require 
a power of about 400 linear to render them distinctly to the eye. 
The nearest allied species to this sponge is our British Halichon- 
dria couchii. In size and external form they are very different from 
each other ; but structurally, as regards the dermal and skeleton- 
tissues, they so closely resemble each other as to render it very 
difficult to separate them. Fortunately the abundance of bibhamate 
retentive spicula in H. elegantia and their complete absence in 
H. couchii renders the discrimination of the two species easy and 
certain. 
