292 DR. J. 8, BOWERBANK ON THE SPONGIAD&. __[ Apr. 6, 
largest of them measured 5355 inch in diameter. In these smaller 
ones there also exists another peculiarity; and that is that the 
terminal teeth are given off at nearly right angles to the axis of the 
shaft. These peculiarities of the tension and retentive spicula of the 
dermal membrane, combined with the eccentric and singular form of 
the sponge, afford excellent specific characters to discriminate this 
from any other nearly allied species. 
HaLICHONDRIA VARIA, Bowerbank. 
Sponge massive, sessile, variable in form. Surface smooth or 
rough and rugged. Oscula simple, dispersed. Pores inconspicuous. 
Dermal membrane spiculous, reticulated ; rete unispiculous ; spicula 
acerate, stout, same size and form as those of the skeleton ; retentive 
spicula bihamate, simple and contort, minute and slender, very 
numerous. Skeleton-rete compact, uni- or bispiculous ; areas un- 
symmetrical ; spicula acerate, short and stout. Interstitial mem- 
branes—retentive spicula bihamate, simple and contort, slender and 
minute, numerous. 
Colour, in the dried state, dull ochreous yellow. 
Hab. Straits of Malacca (Commodore Parish). 
Examined in the dried state. 
The external characters of this sponge are exceedingly variable. 
Sometimes it appears as a rough and irregular mass, full of small 
ridges and promiuences ; at other times it assumes the form of short 
cylindrical branches, with a surface comparatively smooth, and with 
the oscula well developed and evenly distributed. Notwithstanding 
these striking variations in form, the structural characters are 
exactly the same in every specimen. The most striking specific 
characters are exhibited in the dermal membrane, the unispiculous 
rete of which is a very beautiful object when mounted in Canada 
balsam. ‘The rete is seldom more than one spiculum in width; and 
the areas vary to a very considerable extent in form; and the mem- 
branes filling the areas are in many cases crowded with the minute 
slender bihamate retentive spicula. These spicula are very small 
and slender, and require a power of about 300 linear to define them 
in a satisfactory manner. Their length does not exceed twice the 
diameter of a skeleton-spiculum. 
The skeleton-rete is compact and strongly constructed, with but 
slight approaches to symmetry. The areas are very variable in 
form, and each side rarely ever exceeds one spiculum in length. 
The short stout acerate spicula of which it is formed are the same in 
length and form as those of the dermal rete. Within the mass of 
the sponge there are frequently to be seen interstitial cavities of 
comparatively considerable size; and in the lining membranes of 
these the minute bihamate retentive spicula abound to quite as great 
an extent as in the dermal membrane. I received several small 
specimens of this sponge from my friend Commodore Parish, who 
obtained them from the Straits of Malacca. 
