REPORT ON THE ALCYONARIA. 231 



few in number (generally four) tuul wide ; in the stem they are narrower and more 

 numerous, and separated from one another by thick walls. 



This genus comes nearest to Siphonogorgia, Kolliker, but is essentially distinguished 

 by the fact that the polyps occur along the entire course of the branches, and are less 

 retractile. The habit of the colony is more suggestive of Nephthya. 



Chironephthya dipaacea, n. sj). (PI. XXXVII. fig.s. i, la). 



The colony consists, in the perfect condition, of a tall, straight, ascending stem, whose 

 base spreads over a mass of agglutinated sand. A few branches arise first from the upper 

 third, becoming gradually jioiuted towards their ends; these come off sparsely and at 

 varying angles, they are partly simple and partly provided with secondary branches. 

 Especially in the lower third of the branch-bearing portion there arise short, flat branches, 

 which, after a short course, radiate into numerous secondary branches, and these may 

 again give off twigs. The terminal portions of the stem, branches, and secondary branches 

 are covered with polyps, which are placed at wide intervals from one another and exhibit 

 a spiral arrangement. Only towards the apices of the twigs are the polyps more thickly 

 placed, at the apex itself there are usually two or three close together. The polj^jas 

 exhibit a distinct calyx, which is directed obliquely upwards on the branches, and a well- 

 marked tentacular portion. In the branches the canals are wide ; at the base of each 

 branch there are four, radially arranged. In the barren stem they are more numerous, 

 up to the number of sixteen ; they are of different widths, and arranged radially around 

 a central axis. The thickness of their dividing walls gradually increases from above 

 downwai'ds. 



Height of a colony, 



Height of the barren stem, 



Diameter of the stem, . 



Length of an unramified branch, up to 



Diameter of the same at the base. 



130-150 mm. 



90-95 „ 



10 „ 



38 „ 



4-5 „ 



The basal portion is present only in one specimen. It forms a flat overgrowth upon 

 a mass of agglutinated sand, which it also surrounds laterall}'. At the margin it is 

 divided into lobes and stolon-like processes. It passes gradually into the stem, which 

 remains of nearly the same thickness up to the branches. The stem is oval or irregularly 

 angular in transverse section, but generally compressed on one side ; its consistence is 

 rigid, feebly flexible and brittle. Its wall is incrusted with closely packed, longitudi- 

 nally arranged .spicules, which lie in two or three layers in the mesoderm, and give 

 to the latter the character of a firm layer around the internal canal-system. At its branch- 

 bearing portion the stem expands somewhat, but gradually diminishes towards the blunt 



