320 DR. J. S. BOWERBANK ON THE SPONGIAD^E. [Mar. 18, 



matrix lining the canaliculi ; spicula same as those of the skeleton. 

 Dermal membrane pellucid, furnished with a unispiculous rete. 

 Skeleton stout and strong ; primary and secondary lines both multi- 

 spiculous ; spicula acerate, short and stout. Interstitial membranes 

 pellucid, rarely spiculous ; spicula acerate, slender, few in number. 

 Gemmules membranaceous, round or oval. 



Colour in the dried state light ochreous yellow, or pink in parts. 

 Hab. East Indies (5. P. Pratt, Esq.). 

 Examined in the dried state. 



I received this remarkable sponge, with several others, from my 

 late friend S. P. Pratt, Esq., to whom they were sent by his son 

 from the East Indies. No part of the basal portion remains by which 

 we might have judged of its natural size. In its present condition its 

 colour is light ochreous yellow, with patches of rose-colour or pink on 

 some parts of its distal end ; and this tint penetrates considerably below 

 the dermal surface. In its present state it is very firm and strong. 



The inhalant system affords the most remarkable specific characters. 

 It is elaborately constructed, and is unlike that of any other sponge 

 with which I am acquainted. It consists of numerous pocilla, sunk 

 beneath the dermal surface, each pocillum being covered by an ela- 

 borately constructed lid or shield, contained within a circular area 

 or ring* of closely packed spicula, from the inner margin of which 

 are projected ten conical sacculi, their apices nearly meeting at the 

 centre of the circular area. Many of these areas occur singly, 

 slightly sunk beneath the dermal surface, while others are seen to be 

 two, three, or more in linear arrangement, in short shallow canali- 

 culi ; and in some cases ten or twelve are disposed in a long and fre- 

 quently curved or sinuous canal. The canaliculi do not form a con- 

 nected system : each, whether short or long, is unconnected with the 

 adjoining ones. The canaliculi are all lined with a thin continuous 

 bed or matrix, composed of closely felted spicula, of the same size 

 and form as those of the skeleton, in which the inhalant organs are 

 imbedded, and which connects them with the others in that linear 

 series. All the canals terminate with an inhalant area ; and I have 

 never seen an instance of either the lining matrix or the canal 

 extending beyond the terminal inhalant areas. 



The pocilla are nearly hemispherical ; and the membranes of which 

 they are constructed are abundantly strengthened by numerous spi- 

 cula, of the same form and size as those of the skeleton, dispersed 

 over the surface. The system of conical sacculi by which a pociilum 

 is protected is also abundantly furnished with spicula, which are fre- 

 quently projected from the apices of the cones into the open space 

 between their terminations. The external surfaces of the conical 

 sacculi are completely closed, and coated by closely packed spicula ; 

 but the basal portions of their inner surfaces are, for nearly half their 

 length, open, as represented in fig. 8, as if a slice had been taken 

 from each near the middle of its length, in a diagonal direction 

 towards its base ; so that it would appear that the conical organs are 

 impervious to the external water, which enters the hemispherical basin 



