84 A MONOGRAPH OF THE 



hamate attenuated ; and with short, slender porrecto- 

 ternate spicula, mixed in fasciculi which cross each 

 other irregularly. 



Colour. Alive, pallid green. 



Habitat. Island of Fulah, Jameson ; Haaf Banks, 

 Shetland, Mr. Barlee, Mr. J. G. Jeffreys, Mr. Humphreys. 

 Examined. In the living condition. 



I obtained nearly three hundred specimens of this sponge 

 from the Shetland deep sea fishermen through their agent 

 Mr. Humphreys. The largest I have seen was somewhat 

 depressed, and was nearly three inches in its greatest 

 diameter. The smallest did not exceed a large pea in size. 

 They vary in proportions from being nearly globular to 

 about one and a half, their greatest diameter in height. 

 The general description of this sponge by Dr. Johnston in 

 his ' History of British Sponges, 5 p. 83, is very correct as 

 far as it goes. The central nucleus spoken of by that author 

 is simply the concentration of the proximal ends of the 

 fasciculi near the centre of the sponge, and in elongated 

 specimens it is continued upwards as the sponge increases 

 in height. The fasciculi radiate from the short central 

 axis in curves or straight lines, and apparently as often in 

 one way as the other, and there is no difference in the 

 form or size of the spicula from their origin to their termi- 

 nation, when they become intermixed with the defensive 

 spicula of the surface. Their average size is ^th inch 

 long, ^th inch largest diameter. The surface is even, but 

 is pierced in all parts by stout bundles of defensive spicula 

 which originate beneath the inner surface of the dermal 

 crust, among the distal apices of the fasciculi of the 

 skeleton, and project beyond the external surface frequently 

 as much as th of an inch. In the young specimens, these 

 fasciculi consist principally of slender fusiformi-porrecto- 

 ternate spicula, and their furcate apices form very beautiful 

 objects for the microscope, but they are generally broken 

 off in the older specimens. Interspersed with these there 

 are usually a few long, stout, fusiformi-acerate ones, 

 and a few slender but very long fusiform i-recurvo-ter- 



