178 



THE VOYAGE OE H.M.S. CHALLENGED. 



The two calicles figured in the plate are, unfortunately, very badly drawn and 

 obscure, and do not show the pah and columella at all distinctly. 



Extreme height of the largest specimen, 130 mm. Average breadth of the calicles, 

 10 mm. Diameter of the stem at the base of the stoutest specimen, 12 mm. 



Station 320. Off the mouth of the Rio de la Plata. 600 fathoms. 



Lopkohelia. 



Lophohelia prolifera, Milne-Edwards and Haime (Hist. Nat. des Cor., vol. ii. p. 117). 

 (PL VIII. figs. 7, 8.) 



This coral, so abundantly dredged by the "Porcupine" Expedition, and obtained 

 also in deep water by the American expeditions, was dredged only four times by the 



Lophohelia prolifera (M.-Edw. and H.). Three-fourths the natural size. 



Challenger, but once in very great abundance. The specimens then obtained showed 

 great varieties in their form, and, amongst others, examples of Professor Martin Duncan's 

 variety gracilis. 1 Professor Duncan has dwelt at length on the structure, affinities, and 

 varieties of this species in his memoir on the Madreporaria of the Deep Sea. 2 



1 Madreporaria of the Deep Sea, part i. p. 332, pi. xiii. figs. 1,2. " Ibid., part i. p. 328, et seq. 



