REPORT ON THE ALCYONARIA. 6 



verticillate {Dasi/f/orgia, Chiysogorgia). The brauching takes place on the priuciple of 

 the uniparous helicoid cyme ; i.e., the branch gives off twigs on one side which again 

 bear lateral twigs in the same manner. Tliese may again bear lateral twigs of from the 

 second to the fifth order. At the point where each twig comes off the branch or twig is 

 bent at an angle in the opposite direction. The same occurs in the stem at the points 

 where the branches are given off. If there are only a few branches in a spiral and the 

 nodes are many, then the stem appears to be bent in a zigzag manner. 



The coenenchyma is usually thin, and in the younger branches allows the colour of 

 the axis to show through. The polyps are large, and either stand at right angles to 

 the stem or branches or are directed obliquely towards the aj^ex of the branches. On 

 the stem and branches they are placed far from one another, on the branches that sub- 

 divide into twigs there is only one on each node. The tentacles are not capable of being 

 withdrawn into the body ; in repose they simply fold themselves together over the opening 

 of the calyx. 



In addition to the tentacle-bearing polyps there are in many species {Iridogorgia, 

 Dasygorgia) wart-like zooids. They have a laterally placed oral opening and a terminal 

 cushion of ectoderm, which is filled with thread-cells. From their body cavities canals 

 are given off, which open into the longitudinal canal system. 



The axis is horny and arises direct from the purely calcareous basis. It contains, 

 besides the chitinous lamellae, especially in the stem and the thicker branches, a calcareous 

 deposit, which often imparts to it a brittle consistency. In the finer twigs the horny 

 substance predominates and so gives rise to flexible, elastic rods. The surface of 

 the axis appears shining and exhibits iridescent colours which give it a metallic, or 

 mother-of-pearl-like lustre. 



A microscopical examination of the surface of the axis shows the presence of fine 

 calcareous granules on the outermost chitinous layer, arranged in a peculiar order. 



The spicules in the coenenchjTna and in the polyps are transjjarent, glass-like spindles 

 or scales, which form a superficial and a deeper layer. They are sometimes smooth, 

 sometimes provided with fine spines and warts, and lie close together, frequently over- 

 lapping one another at the edges. In the polyps they are placed either transversely or 

 longitudinally, and in Dasygorgia and Chrysogorgia are continued into the tentacles, but 

 the pinnules, which are folded towards the inside in repose, are free of spicules. 



This subfamily equals the family Chrysogorgidse established by VerrilP to include the 

 genus Chrysogorgia of Duchassaing and Michelotti, and two new genera, Iridogorgia 

 and Dasygorgia. Verrill gives the following diagnosis of the family : — " Coral variously 

 branched, the branches most commonly taking a spiral arrangement. Axis partially 

 calcareous, generally with a brilliant iridescence and metallic lustre. Base in most of the 

 species calcareous and divided into irregular, divergent, root-like processes, but usually the 



' Loc. cit. 



