REPORT ON CORALS — HYDROCORALLIN'.E. 65 



is, in some respects, somewhat diagrammatic, but is taken from an actual transverse 

 section. The section is taken above the level of the gastrozooicl, which hence does 

 not appear. The sac of the gastrozooid is, however, seen in section, together with 

 its radial supports. The dactylozooids seen in section show the three layers of tissue 

 of which they are composed, viz., ectoderm, basement membrane and muscular layer, 

 and endoderm ; and sections of their styles are introduced to show the position 

 of these. The two finer reticulations of the coenosarcal meshwork, inner and outer, 

 are also well seen, with the larger canals in the interval between them, which at 

 this height in the wall of the system are confined to the interspaces between the 

 dactylozooids. 



Gonophores. — Male examples only were obtained of the present species. The 

 ampulla? are covered by the surface layer of the ectoderm, and the superficial reticula- 

 tions of the coenosarcal meshwork. Within, they contain a sac (PI. VI. G) in which 

 are developed two or three gonophores of an ovoid form, which are attached to offsets 

 of the coenosarcal canals, and which show the usual elements characteristic of the 

 various stages in the development of spermatozoa in the family, which elements are 

 massed around a spadix, as in Sporadopora. The process of development was not closely 

 followed in the present species. 



Astylus, Moseley. 



I formed the above genus for a Stylasterid with regular cyclo-systems, dredged 

 off the Meangis Islands in 500 fathoms. The coral is, like Cryptohelia,, devoid of 

 styles in both kinds of zooids, and differs in structure in no important particular from 

 that genus, with the exception that it has no solid lid-like covering overhanging the 

 mouths of the zooid pores. It possesses, however, a curious tongue-like process deeply 

 seated in the calicle, which probably is the homologue of this lid. 



Ccenosteum of Astylus subviridis. 1 



The ccenosteum (PI. I. fig. 4) consists of a short stem, which breaks up into a few 

 primary branches. These, with their slender secondary branches and branchlets, 

 which are very few in number, ramify in the same plane, and form a small flabellum. 

 The stem and branches are circular in transverse section throughout their length, 

 except where distorted by the presence of zooid cyclo-systems upon them. They are 

 composed of a hard and compact pearly-white calcareous tissue, the outer surface of 

 which is marked by a series of conspicuous fine rounded ridges, which, separated by 



1 The Hydroid here named Astylus subviridis was referred to in my abstract paper on the Structure of the Stylasteridse 

 (Proc. Roy. Soc, 1876, p. 95) aB "a Stylaster resembling Cryptohelia." 



(ZOOL. CHALL. EXP. PART VII. — 1880.) Cr 9 



