CALCAREOUS SKELETON OF THE ANTHOZOA. 531 



edge zone and in the intra-calicular part of the polyp. (Not 

 all specimens of Caryophyllia have an edge-zone, but il is well 

 developed in some.) 



In the latter situation the calicoblasts seem to serve chiefly 

 for the formation of desraocytes, for they thin out to an almost 

 unrecognisable layer in the areas between the mesenteries. 

 But in the angles formed by the folds of tissue over the edges 

 of the septa the larger granular cells may be distinguished just 

 as in the macerated preparations. The remarkable thing about 

 these calicoblasts is that they do not form a single or a regular 

 layer of cells. There are, in fact, no separate cells, but tliere is 

 a layer of very much vacuolated protoplasm containing nuclei — 

 some I have observed undergoing division, — and the protoplasm 

 seems to be " concentrated," i. e. to be more finely vacuolar 

 and granular in certain places. In many places, as seen in 

 surface view, there are hollows in the protoplasmic mass sur- 

 rounded by ridges of the more vacuolar protoplasm, and the 

 hollows are lined with finely granular cells, if one may apply 

 the name to such a tissue as is shown in fig. 40. 



Two other structural elements could be distinguished. The 

 one consisted of the ovoid bodies with which I was familiar 

 in Alcyonarians. In Caryophyllia these generally showed 

 traces of a filament coiled up spirally within, and hence my 

 conjecture that they are degraded nematocysts. The other 

 structure is shown in fig. 30. It consists of a little eminence 

 in the vacuolar protoplasm forming a ring or half-hoop, with 

 a concavity in the centre, and the walls surrounding the 

 concavity are striated as shown in the figure. These only 

 occur at the sides of, and not actually on the edge of a septum, 

 and they are probably rudimentary desmocytes, serving the 

 same purpose of attaching the soft tissues to the corallum. 



The soft tissues covering the pali in Caryophyllia corre- 

 spond exactly with those covering the septa. Among the corals 

 which formed a part of the collection of the late Mr. George 

 Brook were some very well-preserved specimens of a species of 

 Euphyllia. As I only have specimens embedded in paraffin 

 or in balsam I have been unable to determine the species ; a 



