BRITISH SPONGIADiE. 79 



2. Halyphisema ramulosa, Bowerbank. 



Sponge. Pedicelled, ramose ; branching dichotomously ; 

 branches cylindrical, smooth, and even ; distal termi- 

 nation sub-globose, hispid. Oscula and pores incon- 

 spicuous. Dermal membrane thin and translucent. 

 Skeleton. Membranous, with an incorporation of 

 fragments of spicula of various sizes and shapes, and 

 of minute grains of san9. 



Colour. — Cream white when dried. 

 Habitat. — Guernsey, Rev. A. M. Norman. 

 Examined. — In the dried state. 



This little sponge was found by the Rev. A. M. Norman 

 on a fragment of the skeleton of an old Gorgonia verrucosa, 

 brought up by the dredge off Guernsey. The specimen 

 does not exceed two lines in height and about the same in 

 breadth, and in this space there are eight branches deve- 

 loped, they are all of the same diameter, and each termi- 

 nates in a bulbous expansion, of a rather depressed form, 

 from which numerous large spicula are projected forward 

 at various angles. The parietes of the tubular body are 

 very thin, and the outer and inner surfaces rarely exhibit 

 any projecting parts of the heterogeneous materials com- 

 posing it. In its construction it seems to have appropriated 

 fine particles of sand and fragments of spicula indifferently. 

 The fragments of spicula are very various, some are of large 

 diameter, others very slender, but all seem to have under- 

 gone an approximation towards an arrangement, being dis- 

 posed in the same plane, and they are frequently parallel 

 to each other. There is also a method apparent in the 

 selection and incorporation of the extraneous material of 

 the skeleton that is very remarkable' ; the grains of sand all 

 appear to be within a certain range in size, and beyond 

 this all large ones seem to be rejected. In like manner, 

 the fragments of spicula embedded in the parietes are all 



