30 DR. J. S. BOWERBANK ON CEYLONESE SPONGES. [Jan. 7, 



nating more or less hemispherically, furnished abundantly -with 

 large and small defensive and skeleton-spicula projected from all 

 parts of their surfaces at various angles ; large skeleton-spicula 

 flecto-attenuato acuate, stout and strong, usually procumbent on the 

 tubuli ; small defensive spicula subflecto-attenuato acuate, incipiently 

 spinous, small and slender. Interstitial spicula the same as those of 

 the skeleton, dispersed, numerous. Sarcode blood-red. 



I received this very remarkable sponge among the series of spe- 

 cimens from Ceylon, collected by Mr. Holdsworth. There is no 

 other genus with which I am acquainted to which it can be referred 

 but Haliphysema. The only two species known and described are 

 remarkably small, one consisting of a single simple fistulous skeleton, 

 and the other of a ramous fistulous one ; the species under consider- 

 ation consists of a congregation of numerous single fistulse. Although 

 varying from each other greatly in size, there is a perfect accordance 

 in the principle of their skeleton-structures,'all of them exhibiting the 

 tubular form, with the distal termination closed and more less dilated, 

 that especially characterizes the genus. 



There are no distinct indications of any recent attachment of the 

 sponge. The position of its natural base is indicated by the con- 

 vergence of the skeleton-tubes at their proximal extremities ; and it is 

 probable that the specimen had been freely floating about in a living 

 condition for some time before it was taken. 



There are several large irregular openings on the upper surface of 

 the sponge, which extend deeply into its mass. These orifices have 

 none of the characters of excurrent or cloacal ones. As the internal 

 structures, both in form and mode of disposition, strongly indicate 

 a carnivorous habit in the sponge, it appears highly probable that 

 these large irregular orifices are provided for the double purpose of 

 the admission of water to its tubuli and to allow of the free entrance 

 of minute annelids and other similar prey on which it subsists. 



The skeleton-tubuli are not closely packed together, and there is 

 frequently a considerable space between them ; and the projection of 

 the defensive spicula from their surfaces maintains this separation 

 from each other, their adherent connexion being accomplished by a 

 loose arrangement of interstitial skeleton-spicula, between which there 

 is ample space for the admission and flow of water amongst the 

 skeleton-tubes. 



If this reading of their history from their structure be correct 

 (and it is quite in accordance with what we know to occur in other 

 carnivorous sponges abounding in especial organs for the destruction 

 of intruders within their interstitial cavities), the inhalation through 

 the parietes of the tubes will be as in the other species of the genus, 

 and the excurrent streams will take place in their natural positions 

 at the distal ends of the tubes, which project from the surface of the 

 sponge, and form the numerous minute mamillae of the dermal 

 surface. 



On fig. 2, Plate VII., representing a single skeleton-tube, near the 

 distal end, at a, there is a minute, rather long and very sinuous 

 tube or skin of what appears to have probably been a slender annelid. 



