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



Unfortunately the polyps are very badly preserved, so that I have been unable to obtain 

 much information from a study of sections. They are distributed in two rows on opposite 

 sides of a branch ; sometimes they are arranged alternately one length or more apart, at 

 others they are subopposite. It appears probable that there must be some collection of 

 circular muscular fibres representing a sphincter (Rotteken's) muscle, as the tentacles may 

 be completely covered by the margin of the body-wall when in a state of contraction. The 

 tentacles are thick fleshy processes, having a length equal to the height of a polyp, and 

 bear eight or ten digitiforin branches of variable length (PI. X. figs. 3, 4). The uumber 

 of tentacles is uncertain, but I think it probable that there are only six. I am also at 

 present unable to give any definite information as to the number and arrangement of the 

 mesenteries. 



Habitat— Station 343; March 27, 1876; lat. 8° 3' S., long. 14° 27' W., off 

 Ascension ; depth, 425 fathoms ; bottom, volcanic sand. 



Species incert^ sedis. 



Nearly all the forms included in this section are probably good species, but it is at 

 present impossible to assign them a definite generic position owing to the want of 

 information regarding the structure of their polyps. In order to distinguish the generic 

 name Antipathes, in its restricted sense, from the unmodified genus which practically 

 includes the whole of the Au tipathidas, the word when used in the latter sense has been 

 included within square brackets. 



[Antipathes] corticata, Lamk. 



Antipathes corticata, Lamarck, Hist. nat. anim. sans vert., t. ii. p. 306 ; Dana, Zooph., p. 583. 

 Hyalopathes corticata, Milne-Edwards, Coralliaires, t. i. p. 324; Haeckel, Arabische Korallen, 

 pi. i. fig. 6. 



" A. caule parce ramoso, corticato, spinis numerosis echinato, cortice poris nullis " 

 (Lamk., op. cit.). 



Haeckel, in his Arabische Korallen, has given us a figure of a living colony of this 

 species, by which it is seen that the polyps have the tentacles arranged in a radiate 

 manner, the individuals being distributed at various points around the axis, and not in 

 linear series. In this species the polyps are very distant, apparently in two or three 

 irregular rows. I know of no other species approaching it in this respect, but an 

 examination of the polyps is necessary before its generic position can be definitely 



