226 Mr. T. Higgin on a new 



of the horny network ; these openings are sometimes small, 

 measuring 1 -200th of an inch across or even less, and some- 

 times are as large as l-50th of an inch ; but whether large or 

 small, the margin of each is a more or less thickened ring, and 

 they are no doubt sphinctral. The sarcode of this areolar struc- 

 ture is not dark-coloured like that of the dermis, but is almost 

 colourless, and is dotted over with rounded granular bodies, 

 which may be regarded, according to the observations of Mr. 

 H. J. Carter, as the pigment-cells, which, when exposed to the 

 light (as they are in the dermal sarcode), become deeply coloured, 

 and in that condition give the sarcode of the surface its cha- 

 racteristically dark brown or black appearance. It is probably 

 for the same reason that the sarcodic surface-layer of the 

 inside of the tube is not so dark as that of the outside ; but 

 another reason is that it is not so strong. The position of the 

 vents is a good deal obliterated by this tender dermal sarcode 

 having cracked in drying ; they may, however, be fairly traced, 

 occurring in circular lines on the inner surface of the tube, 

 and rather larger than the pore-openings. Thus, as in all 

 tubular sponges, the vents open into the so-called " cloacal 

 cavity," which is but the great excretory canal of the whole 

 sponge emptying itself at the aperture. 



Size. The large individual or tube measures 3 feet 9 inches 

 in length, with a diameter of 2 inches at the small or fixed 

 end, where it rises from the flange-like base ; and one of 5 by 

 4 inches at the other extremity just before it terminates, not 

 being absolutely round at this part. The small individual or 

 tube is 1 foot 7 inches long, its smallest diameter being 1 inch, 

 and its largest 2^ inches. The proportions of the two tubes 

 are therefore similar. But Mr. Archer has subsequently met 

 with another specimen, which is said to be nearly five feet 

 six inches long. 



Obs. The large tube has in the living state doubtless been 

 quite round at its free end, like the small tube ; but it has 

 been placed on its side to dry, in which position the walls, 

 having been heavy with water, have not had sufficient strength 

 to retain the original shape of the tube, but have, by depending, 

 somewhat fallen together ; and consequently, drying in this 

 state, it is not quite round at the free end. 



The only sponge hitherto figured witli which this species 

 might be confounded is that which was described, with illus- 

 trations, by Esper in the volume of ' Pflanzenthiere ' published 

 in 1794, page 222, tab. xx., xxi., xxi. A, as the Spongia Jistu- 

 laris of Linnaeus, and which appears to be also Spongia tubce- 

 formis of Lamarck ; but neither the plates nor the letterpress 



