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



this species has been found by us in the collection. It is not uninteresting to add that in 

 this frao-ment, which is partly growing over the axis of a Gorgonid, the polyps are nearly 

 all extruded, at least theii- tentacular crowns in most cases are displayed. 



Habitat. — Reefs at Samboangan, Mindanao, ^cZe Professor Moseley. 



Station 186, Cape York; depth, 8 fathoms (?on Reef). 



Family II. NEPHTHYiDiE. 



Nephthyidx, Verr., Proc. Essex Inst., vol. vi., 1869, including Siphonctgorgiacex, KoUiker, 

 Festschrift, z. Feier des fiinfundzwanzigjalirigen bestehens der physic.-med. Ges. 

 Wiirzburg, p. 22, 1874. 



SjMggodinee, Dana. 



Spoggodidx, Nephthyadx, Lemnaliadx (pars), Gray. 



Alcyoniens arines, Milne-Edwards {pars), Hist. Nat. des Coralliaires, t. i. p. 127. 



Alcyo7iinx capituliferx et Siphonogorgiaca:, Klunzinger, Korallenthiere des rothen Meeres, 



Th. 1, p. 10, 1877. 



The colonies form upright, branched stems, each consisting of a more or less developed 

 barren trunk, and of branches which ramify very variously and bear the terminal polj^DS. 

 The polyps are not divided into a calycine and a tentacular portion, so that no complete 

 invagination of the upper tentacle bearing part into a lower gastral cavity can take place, 

 and in repose the tentacles are folded over the oral cavity or the upper portion of 

 the body can be withdrawn. The polyps are continued into long gastral cavities, which, 

 however, do not ojjen into one another but become separated from one another by thin 

 walls. Each gastral cavity diminishes in size downwards, until at length it terminates in 

 a wedge-shaped, blind sac. Only a few are continued, in isolated cases, directly into the 

 main canal. 



The trunk and the larger branches are penetrated by sometimes wide and some- 

 times narrower canals. These canals are separated only by thin walls, sometimes 

 with and sometimes without spicules ; they are surrounded on the outside by a thicker 

 external sheath armed with spicules. The large main canals are connected with the 

 long pol)^ tubes by canals which originate at the base of the polyps. There is also 

 developed, in the partitions which separate the polyj) cavities and canals, another system 

 of narrow, capillary " nutrient-canals." From these the young buds arise, between the 

 old ones, which from the commencement of their development possess longer or shorter 

 digestive cavities. In the branches one can usually distinguish four wide canals whose 

 walls are coterminous in the axis of the branch. New polyps, whose narrow tubes 

 appear on transverse section, occur on the outside of the four main tubes, in the spaces 

 between each two, but their boundary walls do not extend as far as the axis. Towards 

 the end of a branch the young polyps constantly increase in number and their digestive 

 cavities become shorter and shorter. 



