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



breadth measure respectively O'S and 0-025 ; 0-35 and 0-016 mm. In the inner stratum 

 of the mesoderm the spicules are spindles with sharp spines, which often present ramified 

 projections at both sides. Sometimes these are straight, sometimes bent, and occasionally 

 two or three are closely united. 



In length and breadth these measure respectively 0-27 and 0-05 ; 0-23 and 0-03 ; 

 0-25 and 0^04 mm. 



In the tentacles spicules occur of the first form, and also simple, smooth, straight 

 or bent needles. 



The colour of the colony in spirit is grayish-white. 



Habitat.— Station 190, in the Ai-afura Sea; lat. 8° 56' S., long. 136° 5' E. ; depth, 

 49 fathoms ; bottom, green mud. 



Telesto (Carijoa.) trichostemma (Dana). 



Gorgonia trichostemma, Dana, Zoopb., p. 665, pi. lix. figs. .3, 3«, 3?;, 1846. 

 Telesto iriclwsteinma, Verrill, Amer. Journ. Sci. and Arts, vol. xlv. p. 415, 1868. 



Dana described, under the title Gorgonia trichostemma, an Alcyonarian from the Fiji 

 Islands, which in its habit presents a great resemblance to a species of Telesto. Verrill 

 has examined the original specimen and has described it as a parasitic polyp allied to 

 Cornularia, and probably a Telesto. In part it covered the dead a.xis of an A ntipathes, 

 in part it exhibited free hollow branches. 



A Telesto-like Cornularid, which was obtained by the Challenger Expedition in 

 Torres Strait from a slight depth, agrees so well with the representation given by Dana, 

 that we cannot but refer it to the same species. The colony consists of creeping stems, 

 which are beset with lateral poly^^s, and of single upright branches. The stems arise 

 from stolons which cover foreign bodies and form a thick network, sometimes fusing into 

 flattened discs. 



The stems are axial polyps of the first order ; they are at first provided with a thick 

 wall, which gradually becomes thinner in the ascending portion, and this is terminated by 

 the calyx aperture. The creeping portion of the stem attains a diameter of 5 mm., 

 and in old specimens is covered by a parasitic siliceous sponge. In this region the 

 spicules, which lie in the sheath surrounding the gastral cavities of the polyps, form by 

 close apposition a firm tube. In the older portion this is further strengthened by the 

 cementing of the spicules by a horny substance. This horny material gives the tube a 

 yellowish-brown colour, and causes it to exhibit exactly the appearance and consistence 

 of a Gorgonid axis, on which the soft ccenenchyma appears to be cortical. In the 

 younger portion of the stem, the horny substance disappears, and the axial portion has 

 a white colour and a loose consistence. 



Only in the ascending terminal portion of the stem do the spicules cease to be united, 

 so that this region exhibits exactly the appearance of an ordinary Telesto. From one 



