278 Mr. P. H. Gossc on Sarcodictyon catenata. 



would present ; for the form of the stomach here, as in Alcyo- 

 nium and the Actinio'ids, is that of a flattened sac, or that which 

 a pillow-case would take, supposing it to be suspended longitu- 

 dinally, and both ends to be unsewed. The inferior extremity 

 of this long sac, which hangs down in the centre of the column, 

 sustained in place by the eight septa, which connect it through- 

 out its length with the column-wall, is entirely open, without 

 the slightest constriction or appearance of a sphincter. It is 

 in fact a little dilated, and runs off into eight produced points, 

 coinciding with the septa, which pass off thence downward to- 

 ward (and probably to) the bottom of the visceral cavity. The 

 free edges of the septa, below the termination of the stomach, 

 are thickened and much convoluted, each forming doubtless a 

 craspedum ; but the distinct sight of their structure is speedily 

 lost in the swollen masses, of an opake pale-red hue, into which 

 they merge, and which nearly fill the cavity, — doubtless the 

 ovaries. 



It is remarkable that the most careful scrutiny failed to detect 

 even a single spiculum in the texture. In Alcyonium these depo- 

 sits are found by hundreds around the neck of the polype and 

 running up into the tentacles, as well as in the skin of the co- 

 lumn. But in my expanded Sarcodictyons none could be detected 

 in the tissues of the living animal ; and examination of the 

 dead proved equally fruitless : for I separated one, pressed it to 

 actual flatness between the plates of the compressorium, and 

 allowed it to dry ; then I treated it with a solution of caustic 

 potash (Brandishes) ; finally I boiled the remains in the potash 

 over a flame for some minutes ; but with the most careful search, 

 under a magnifying power of 600, and subsequently of 800 dia- 

 meters, not a single spiculum appeared. I may observe, by the 

 way, that after these processes the form of the pressed animal, 

 and particularly of the tentacles with their pinnae, remained 

 perfect, whence I infer that the integument is of a chitinous 

 nature. 



On the other hand, the spicula were conspicuous enough in 

 a dried specimen of Sarcodictyon similarly treated. Dr. Battersby 

 had kindly given me a fine specimen of this species in the 

 dry state, which he had dredged this summer on the coast of 

 Galway. From this I cut off a small portion of the band in- 

 cluding a single polype ; and having macerated it in water and 

 subjected it to boiling potash, I found the spicula conspicuous, 

 though not very numerous. They were, in fact, distinctly iden- 

 tifiable with a power of 65 diameters, being on an average "003 

 inch in length, and some attaining to *0055. These spicula 

 were of a transparent light-red hue, and of that pattern (though 

 varying indefinitely in detail) which I have represented, in my 



