BRITISH SPONGIADjE. 69 



habit of this little sponge is veiy singular. The shape is 

 that of an oval battledore with a handle more or less long, 

 adherent to the substance to which it is attached for its 

 whole length, by one of its broad surfaces. .The body of 

 the sponge in both specimens is nearly of the same size 

 and shape, but the mammeeform cloacal appendage in one 

 is only half a line in length, while in the other it is half an 

 inch; in other respects, they resemble each other very 

 closely. The shorter of the two specimens is from Shetland 

 and is in a finer state of preservation than the one from 

 Peterhead. I have, therefore, selected it for description. 



The length of the body is a line and a half, and its 

 greatest breadth rather exceeding a line and a quarter; 

 the cloacal appendage is half a line in length, and its 

 medium breadth not quite a quarter of a line ; its smallest 

 diameter being at its apex, and its greatest breadth at the 

 parts whence it springs from the body of the sponge. 

 There are no indications on either specimen of the sponge 

 ever having been in an erect position ; on the contrary,both 

 specimens are attached in precisely the same manner to the 

 fragments of bivalve shells on which they were based, not 

 by a few isolated points but by a close adherence of the 

 whole surface. The entire thickness of the sponge does 

 not exceed that of a sheet of writing-paper. Having care- 

 fully removed the specimens from the shells and mounted 

 them in Canada balsam, in the cloacal appendage there 

 appeared three large longitudinal fasciculi of spicula, the 

 intervening spaces being almost equal in breadth to the 

 diameter of the fasciculi, and their bases can be traced for 

 a considerable depth in the body of the sponge. In the 

 second specimen in which the cloacal appendage is very 

 much longer, there are as many as j&ve of these fasciculi 

 which divide and anastomose repeatedly in their course to 

 the apex of the cloacal appendage. 



On the under side of the cloacal appendage there are 

 numerous small spinulate spicula, crossing the large primary 

 skeleton fasciculi at right angles to their axes in an irregu- 

 larly matted manner ; and the margins of the cloacal ap- 

 pendage are armed with numerous external defensive 



