REPORT ON THE ALCYONARIA. 221 



The stem, which is attached to the rocky substratum by means of a broad base and 

 shows no development of stolons, gives off on all sides, and at tolerably wide distances 

 from one another (viz., 5 to 8 mm.), larger branches, which resemble the main stem, and 

 small branchlets which surround the stem and larger branches equally. These branchlets 

 are flattened, from the base outwards, in a direction at right angles to the long axis of 

 the colony. They are sparsely ramified in one plane, and each usually divides into two 

 or three twigs diverging from one another at obtuse angles. From the sides and apex of 

 the twigs the polyps arise, they are placed on long peduncles and surmounted by spicules. 



One twig thus bears from five to eight polyps, which sometimes come off at right 

 angles and sometimes radiate, at the apex, in a fan-like manner. The flat twigs some- 

 times fuse together, especially towards the base of the stem, so as to form serrated folia, 

 whose margins are covered with divergent polyps. Or the branches and twigs may be 

 fused together immediately above the base so as to form a collar-like pad, convex down- 

 wards, from which the divergent polyps originate. The branches and twigs are soft and 

 yielding, and the entire colony has a spongy consistence. The stem and branches are 

 covered with spindle-shaped spicules, arranged irregularly and crossing one another. In 

 the branchlets and twigs they are arranged in longitudinal series, and they are continued 

 into the peduncles of the polyps, of which one spicule projects like a spine above each 

 pol}^ head, for a distance of 1 mm. at the most. These spicules are partly straight and 

 partly y^shaped, and they are covered with small, sharp spines ; their length varies from 

 0"8 to 5"0 mm. ; the latter occurring especially in the polyp-peduncles. Length to 

 breadth, fS by 0-032 mm.; 4'0 by 0-09 mm.; 5-0 by 0-12 mm.; 5-0 by O'OIS mm. 



The polyp heads are small, measuring 0"8 mm. They have at their bases a number of 

 peripherally arranged spicules, from which eight larger ones arise, surmounting the margin 

 of the calyx. These spicules are truncated at the base, pointed at the free end and 

 provided with small, straight spines; size, 0"58 by 0"03 mm. Some convergent spicules 

 at the base of the tentacles form a kind of operculum to the calyx. In the tentacles 

 there occur small spicules. The smaller spicules of the polyp heads measure 0'36 by 

 0-025 ; 0-2 by 0-033 ; 0-3 by 0-018 mm. 



The colour of the colony is white, the twigs and polyps at the base and over half the 

 extent of the colony are purplish-red. 



Habitat.— Tahiti ; depth, 30 to 70 fathoms. 



The description of the following species will make this section more complete : — 



Spongodes semperi, Studer. 



Spongodes semperi, Studer, Ann. and Mag. Nat. Hist., ser. 6, vol. i. p. 69. 

 A thick, cylindrical, barren trunk, whose base is fixed in the sand by means of 

 stolons. It gives off from its upper end, which is bounded by a circular fold covered on 



