168 THE VOYAGE OF H.M.S. CHALLENGER. 



The ccenench}Tna is thin, and is densely packed with an outer layer of spiny or warty 

 spindles ; some of these spicules lose the elongated spindle shape, becoming almost 

 orbicular. Under this layer and extending up into the verrucas, smaller spiny spindles 

 are met with, some of which show a tendency to assume the double spindle form, which 

 is so characteristic of the other species of this genus. The eight-rayed edges of the 

 verrucae contain also small narrow spiny spindles. A colleret of smooth and spiny acerate 

 spicules surrounds the bases of the tentacles, and a few minute spicules are to be found on 

 the outer portion of each tentacle, which on the withdrawal of the polyp form an opercular 

 covering. 



The colour of the colony in spirits is a yellowish-brown. 



The spicules measure as follows: — The larger warty spindles 0'4-0"12; 0'4-0*l ; 

 0-4-006 ; 0-38- 0-1 ; 0-28-0-1 ; 0-26-0-1 mm. The smaller spindles 0-2-0-06 ; O'l 8-0-06 ; 

 0-12-0-04 ; 0-1-0-02 mm ; those of the tentacles 0-2-0-02 ; 01-0-02 mm. 



This species has the largest and most prominent polyps of any of the known 

 species. 



Habitat. — Along with Suberogorgia verriculata (Esper) at Station 232, Hyalonema- 

 ground, off Japan ; depth, 345 fathoms ; bottom, green mud. 



Genus Keroeides, n. gen. 



Axis sclerogorgic, i.e., consisting of a central core which is made up of bundles of 

 long, narrow, smooth, spindle-shaped spicules, agglutinated and partially intercalated 

 with one another ; the nutrient canals surround this central core ; the ccenenchyma 

 being moderate and friable. 



The colony consists of a much branched stem ; the polyps are placed on either side of 

 the stem and branches, on slightly prominent verrucse, which from their bilateral arrange- 

 ment give a somewhat flattened appearance to the branches ; the space free of polyps 

 forms a well-marked groove running down the centre of the stem and its branches. 



The ccenenchyma consists of large, massive spicules, mostly of warty spindles, which 

 appear covered with a somewhat dense spiculiferous capsule. The verruciform pro- 

 minences contain smaller warty spindles ; while minute spiny acerate spicules are to 

 be found in the tentacles of the polyps. 



The polyps are retractile, the edges of the verrucas folding in over them forming an 

 oval eight-rayed star. 



Duchassaing and Michelotti describe under the name of Acis nutans, n. sp., a 

 form taken at Santa Cruz, which judging from their description and still more from the 

 apparently well executed figures, cannot belong to the genus Acis. While the type 

 specimen of Acis guadaluperisis, Duchassaing and Michelotti, still exists, very un- 

 fortunately there is no trace of their Acis nutans. 



