348 A MONOGRAPH OF THE 



as it was cut into numerous pieces by the dredge, which 

 appears to have taken it from- a nearly level surface. Some 

 of the pieces of the basal portion are about two and a half 

 inches in diameter, and several others somewhat less, and 

 when placed closely together they fill a space of not less 

 "than seven inches square, and besides these fragments there 

 are nearly twenty large cloacae, for which no positions are 

 apparent on the pieces of the basal masses of the sponge in 

 my possession; the probability therefore is, that in its 

 perfect condition it would have exhibited a surface equal to 

 at least a foot" or fourteen inches in diameter. The thickest 

 fragment of the basal mass does not exceed about an inch. 

 I could not detect oscula on any parts of the massive 

 base of the sponge. 



Prom this basal mass numerous penicellate tubular cloacae 

 spring, varying from half an inch in height and two lines 

 in diameter, to four inches in height and three fourths of 

 an inch in diameter at the base, usually decreasing gra- 

 dually in size to the distal extremity, and terminating in a 

 contracted, apparently permanent, orifice. The central 

 tube at the base, in large specimens, frequently exceeded 

 four lines in diameter. In one case the base was dilated 

 into the form of a hydrometer bulb, exceeding an inch in 

 diameter. The parietes were very thin, and the cloaca at 

 the base springing from the top of the bulb was only four 

 lines in diameter, and continued of that size to very near 

 its distal termination, at rather more than two inches in 

 height ; the central cavity was open throughout ; this 

 variation in form is evidently abnormal. 



In the perfect sponge the number of these organs must 

 have been very considerable, as I have the remains of more 

 than thirty of them of various' sizes, and in one fragment 

 of the sponge, about three inches in diameter, there are 

 eight of them of various sizes. The smaller tubes all 

 appear to be simple, but the larger ones occasionally throw 

 off" one or two short tubular branches. The parietes of the 

 larger cloacal tubes is frequently a quarter of an inch thick 

 at the base, and it gradually becomes thinner to its distal 

 extremity, where it is not thicker than a sheet of paper. 



