EEPOET ON THE ALC YON ARIA. Ill 



The known species are found in the troijical seas of both licmispheres at somewhat 

 moderate depths. 



Villogorgia nigrescens, Duch. and ]\Iich., Guadeloupe. 

 ,, intricata, Gray, Australian Seas. 

 „ gracilis, Studer, Bougainville. 

 „ mavritiensis, Ridlej", Mauritius. 

 ,, Jlabellata, Gray. 



Of these only the following one is in the collection of the Challenger : — 



Villogorgia intricata (Gray) (PL XXIII. fig. 3, a, h ; PI. XXVII. fig. 1). 



Brandtlla intncata, Gray, Cat. Lithophytes Brit. Mus., p. 30, fig. 8, 1870. 

 Villogorgia intricata, Ridley, Ami. and Mag. Nat. Hist., ser. 5, vol. ix. p. 188, 1882. 



The diagnosis of this species, which despite its transparent horny axis was in a 

 very curious way placed by Dr. Gray among the Corals with calcareous axes, is emended 

 by Ridley, who gives full details about the spicules. 



The Challenger specimen agrees in all its details with the t5^pe in the British 

 Museum, but it is a faii'ly complete specimen, whUe the original specimen only 

 represents the fragment of a colony. The colony is upright, richly branched in one 

 plane, with numerous branches whose terminal twigs sometimes anastomose. The 

 principal stem arises from a horny base which grows over a stone ; the base is cone- 

 shaped ; the main axis gives off near the base a large lateral branch, by which it is 

 diverted from a vertical position and becomes slightly inclined to one side. The 

 branches arise from both sides of the stem, at an angle of 50°, irregularly alternate, but 

 more numerous on the convex side than on the concave. From the branches lateral 

 twigs which stand off perpendicularly arise. Some bend after a short perpendicular 

 course, and then run parallel with tlie liranch ; others run .straight to the nearest 

 branch, with which they anastomose. The branches often give off others of the second 

 order, which behave similarly. The terminations of the branches and twigs which do 

 not unite remain free for a considerable extent. The height of the colony is 125 mm., 

 its greatest breadth is 150 mm. The length of the principal stem is 120 mm., that of 

 the larger branches 100 to 110 mm. The thickness of the principal stem at the base is 

 3 mm., of the larger branches 1-5 to 2 mm. The free terminal branches reach to 

 20 mm. 



The coenenchyma is thin, on the older portions of the colony it is translucent. 

 The polyps rise perpendicularly from the stem and branches, mostly from either side, 

 and at irregular intervals of 1 mm. The termination of a branch is occupied by a 

 polyp. The polyps measure 0'5 mm. in height by 0'54 mm. in breadth. The 



