CALCAREOUS SKELETON OF THE ANTHOZOA. 529 



more defined^ and the desmocyte, wliich was at first separate 

 from the mesogloea, becomes attached to it by a process deve- 

 lopedj as it seems, at the expense of neighbouring cells. In its 

 final condition the desmocyte may be of various shapes — 

 twisted as in fig. 39; or of a well-marked goblet shape. I have 

 no doubt that Fowler (9) was right when he ascribed to the 

 desmocytes the function of fastening the soft tissues to the 

 corallum, though they do not appear to be mere processes of 

 the mesogloea; as he described, but structures sui generis, 

 developed at the expense of cells otherwise indistinguishable 

 from calicoblasts. 



I claim^ therefore, that not only their position, but also their 

 microscopical structure, their development, and their behaviour 

 under the polariscope, show that the desmocytes are not coral- 

 secreting cells. 



But if they are not, some further information is required as 

 to how the corallum is formed, and as to what are the histolo- 

 gical characters of the calicoblasts which form it. And the 

 existence of the scale-like calcareous structures described and 

 figured by Mrs. Gordon has to be accounted for, since it is evident 

 from what has preceded that these cannot be calcified desmocytes. 



In order to determine these questions I made a number of ob- 

 servations on Caryophyllia Smithii, this being the only coral 

 which I could obtain living. If a Caryophyllia be killed in 

 a five per cent, solution of osmic acid, stained for twenty 

 minutes in picro-carmine, and then placed in glycerine, the soft 

 tissues may, with the exercise of a little care, be readily re- 

 moved from the exsert portions of the septa ; but it is best to 

 cut out the septa carefully with a stout pair of scissors, and to 

 remove the tissues from the fragments of the septa with needles 

 and acamel's-hair brush. The corallum is found to be every- 

 where covered by an exceedingly fine membrane, consisting on 

 the one side of very flat endoderm cells, forming a sort of pave- 

 ment epithelium. I noticed in these cells a peculiar structure, 

 which is shown in fig. 26, and it may be described in passing. 

 Each endoderm cell bears a rather long flagellum, and the 

 flagellum may be traced to a minute prominence in the neigh- 



