REPORT ON THE ALCYONARIA. 121 



diameter of 2 mm. at their commencement and 2 "5 mm. at their thickened ends. The 

 stem and branches are not cylindrical, but flattened on the two sides, so that the longer 

 diameter comes in the plane of the expansion of the stem. The coenenchyma is thick 

 and rough. The polyps form prominent, blunt, conical warts, with a basal diameter 

 of from 1 to 1'5 mm. They have a conical operculum. The polyps are found all 

 over the surface of the twigs and finer branches ; on the larger flattened branches 

 they occur only on their shorter diameter ; while on the main axis one surface alone 

 has polyps, the other having none. The spicules of the ccenenchyraa are smooth 

 spindles, placed close to one another, their long axis parallel to that of the stem ; one 

 end of the spindle terminates in wart-like protrusions, with dentate margins, which inter- 

 calate with those of the adjoining spindle ; the other is expanded into irregularly shaped 

 longish discs, with dentate margins and warty surfaces. Their length by breadth is 

 0'33-0'08 ; 0"3-0'l mm. The spicules are arranged peripherally round the base of 

 the polyps, usually in two rows ; their dentate surfaces projecting beyond the 

 coenenchyma and giving it a spiny appearance. These one-sided spiny discs and 

 spindles, when viewed in profile, remind one of a hairy caterpillar, or still more of an 

 jEoUs ; their length is 0'6 mm.; the spiny warts are 0"13 to 0'25 mm. long. On the 

 polyps the spiny portion of the spicule is more strongly developed, and there are spiny 

 discs 0"3 mm. long by 0'2 mm. broad; towards the margin of the calyx stellate 

 spicules, with projecting smooth spines, are met with. From the projecting portions of 

 these spicules, which lie over one another like tiles on a roof, a roughened appearance is 

 given to the calyces. Spindle-shaped spicules, at the base of each tentacle, with spiny 

 margins, form the opercular covering ; there are three spicules at the base of each 

 tentacle, 0"26 mm. long and 0'06 mm. broad ; they rest on a well-developed colleret of 

 curved and peripherally placed spindles, which can be withdrawn within the margin of 

 the body. 



The axis is horny, fibrous, of a black colour in the stem, but a light brown on the 

 thinner branches. 



Habitat. — Station 201, Philippine Islands; depth, 120 fathoms 



Genus 11. Acis, Duchassaing and Michelotti. 



Acis, Duoh. et Mich., M^m. Corall. des Antilles, p. 19, 1860 ; Suppl. Mem., p. 14, 1864. 

 „ Kolliker, Icones Histiologicae, p. 136, 1865. 

 „ Ridley, Ann. and Mag. Nat. Hist., ser. 5, vol. x. p. 126, 1882. 



This genus was established by Duchassaing and Michelotti for a West Indian 

 species, conspicuous for the great development of the spicules. The diagnosis given 

 in the Supplement, which includes two species, is : — " Polyparium ramosum, cortice e 

 spiculis magnis fusiformibus nudis vel etiam in superficie squamulis deciduis formato ; 



(ZOOL. CHALL. EXP. PART LXIV.^1887.) SsS 16 



