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



radial masses thus derived splits again. Thus, in the entire coral there are forty-eight 

 radially-disposed masses of soft tissue occupying the corresponding septal interspaces. 

 The anatomy of the coral was not followed further, none of the specimens being in very 

 good condition, having mostly suffered from breakage and delicpiescence before reaching 

 the surface. Some specimens contained numerous large ova. 



Cycloseris. 

 Cycloseris tenuis (PI. X. figs. 6, a). 



Fungia tenuis, Dana, Zooph., 1846, p. 290, pi. viii. fig. 1. 



MM. Milne-Edwards and Haime considered Dana's Fungia tenuis from the Pacific 

 Ocean as probably identical with their Cycloseris sinensis. 1 Fungia sinensis has, how- 

 ever, according to their description, eight complete cycles, whereas Dana's has only six 

 systems, and instead of being circular is subangular. The Pacific species thus seems to 

 be distinct. I figure a specimen dredged off Tongatabu. 



Diameter of the corallum, 20 mm. Extreme height from centre of the base to the 

 inner tip of the septa, 5 mm. 



Station 172, off Tongatabu, Friendly Islands. 18 fathoms. 



Family Eupsammid^e, Milne-Edwards and Haime. 

 Balanophyllia. 



Balanophyllia bairdiana, Milne-Edwards and Haime (PL XII. figs. 4-7). 



Four specimens, dredged in 40 fathoms off the South Australian coast, seem referable 

 to the above species, of which the type is in the British Museum. Two of the specimens 

 are young, and the other two, though differing in size, apparently adult. The larger adult 

 specimen, on comparison with the type, which is not in good condition, is seen to differ 

 from it in that it has a well marked though very thin epitheca at its base (see fig. 4), the 

 type having almost none at all though adult. The specimen further differs from the 

 type in that its costas are less prominent and its septa more numerous. The larger of the 

 young specimens very closely approaches BalanophyUia Jtorideana, Pourtales (Deep-Sea 

 Corals, p. 41, pi. iv. figs. 5, 6), a specimen of which is also in the British Museum. 



Adult corallum straight, flabelliform or elongate, compressed, conical, with truncated 

 base of attachment much compressed. A thin epitheca present at the base, extending 

 for from one-third to two-thirds the height of the corallum. Costae close set, covered 

 with fine sharp denticulations, formed in the young coral by double rows of granules, in 



1 Milne-Edwards and Haime, Hist. Nat. des Cor., torn. iii. p. 52. 



