126 



small, some mere little raised areas of the wall, packed with bat- 

 teries of nematocysts of the usual type. When the polyp con- 

 tracts, none of the tentacles seem to be capable of being intro- 

 verted, though I., 11., and III. are a little pushed m round tlieir 

 bases. Their protection is rather afforded by the folding in- 

 wards of the edge of the disc of the polyp, brought about by 

 the contraction of a sphincter muscle. The anatomy, too, 

 shows that there can scarcely be any introversion. Indeed, it 

 would seem impossible, as the structureless lamella both of the 

 tentacles and disc is remarkably thick Emd firm. The mesen- 

 teries, too, are attached between the tentacles, and do not seem 

 to send up muscular fibres into them. 



There are 48 mesenteries, septa IV. being exocoelic* 

 I'welve are attached to the base of the stomodoeum, into the 

 wall of which their filaments pass, continuing up as ridges for 

 about a half of its length ; 1 2 also extend down from its mouth 

 for about a third of its depth, but have no corresponding thick- 

 enings. Filaments are found on all the mesenteries, the edges 

 of which are looped, but with no acontial portions. Nemato- 

 cysts only occur sparingly, save in the lower halves of the fila- 

 ments. In none is the black thread, which commonly occurs, 

 distinct, and few have any eversible basal portion at all con- 

 spicuous. Their appearance may be due to the coral having 

 recently been feeding, but is rather, I think, caused by a real 

 degeneracy in them as stinging cells. 



The endoderm is thin, but presents a smooth, even surface, 

 as the inequalities of the corallum are filled in by thickenings 

 in the structureless lamella Food masses are found through- 

 out it, but are more conspicuous in the pads at the bases of the 

 filaments. The sides of the septa are in places packed with 

 nematocysts, lying parallel to their surfaces, and pointing to- 

 wards the mouth of the calicle. They are similar to those of 

 the filaments, but have no trace of any eversible bases and are 

 evidently degenerate. The testes are of the usual type, their 

 follicles presenting all stages of development to be flaggellated 

 spermatoza. 



The corallum is much bored into, especially below the pali 

 and columella, by the filaments of Achy la. 



Note on CARYOPHYLLIA SMITHL— I am indebted to 

 Mr. R. C. Punnett for some well-preserved specimens of this 

 form from 80- 1 00 fathoms, off Bergen, Norway. As compared 

 with C. cfithecata the polyp extends much further down the 

 outside of the corallum. The tentacles number 24, alternately 

 larger and smaller, but where septa V. are present additional 

 ones occur over IV. The structureless lamella is half to a 



* In one specimen there were 50 mesenteries, only 23 septa of IV. being 

 exocoelic. 



