358 COLLECTIONS FROM MELANESIA. 



1 millirn. in diameter at its base, placed on the larger and medium- 

 sized branches. Axis of soft joints firm, brick-red in colour; that 

 of internodes crimson, traversed by numerous longitudinal canals in 

 the stem and larger branches, in the small branches deeply chan- 

 nelled by longitudinal forrows. 



Spicules of general cortex : — (i.) Larger, fusiform, the ends rather 

 blunt, the shaft stout, beset with numerous strong and prominent 

 tubercles, their ends strongly microtuberculate, irregularly distri- 

 buted over the spicule ; size *21 by "062 millirn. (ii.) Smaller, sub- 

 cubical, looking as if formed by an aggregation of tubercles like tbose 

 of (i.) ; diameter *07 millirn. Spicules of verrucae : — (iii.) Longitu- 

 dinal, fusiform, -with blunt ends, provided with numerous and strong 

 tubercles of a length equal to half the diameter of the shaft of the 

 spicule ; size *21 by '035 millirn. (iv.) Horizontal, fusiform, tapering 

 to sharp points, tubercles numerous but small and sharp ; size as (iii."). 



Hob. Port Molle, Queensland, 12-20 fms. 



Two dry specimens represent this beautiful species. The common 

 stem of the largest is 31 millirn. long, its total height 130 millirn. 

 (5 inches), its maximum width 76 millirn. (3 inches). The species 

 differs from M. ocliracca externally by the presence of two kinds of 

 zooids, by the slenderness of the stem, and the slight difference in 

 thickness between the main and the lesser branches, by the greater 

 relative length of the internodes and the rounded outline of the joints, 

 the almost complete anastomosis of the branches, and the whitish 

 ground-colour of the cortex : in its minute characters it is distin- 

 guished by the long cortical spicules being stouter and about half 

 as long again as in M. ochracea, and by the stronger tuberculation 

 of those of the verruca?. Although, as in the cases of Alcyt nium 

 and Sarcophytum, Xenia and Heteroxenia, two otherwise nearly 

 related genera have been shown to be distinguished by the character, 

 of dimorphism in the polypes of one of the pair, I do not know 

 any other case in which, as here, a species is referable on all other 

 grounds but this one character to the same genus as other species 

 which do not exhibit it. 



MOPSELLA. 



Mopsella, Gray, P. Z. S. 1857, p. 28 !. 

 Melitella, Gray, P. Z. S. 1859, p. 485. 



Both hard and soft axis perforated by longitudinal canals wherever 

 stout enough to carry them. Cortical spicules of two kinds, fusiform 

 and foliated (" Blattkeule," Kolliker). The presence of this foliated 

 spicule distinguishes the genus from Jlelitochs and Acalana ; this, in 

 conjunction with the perforation of the hard axis, from Clathraria. 



■ >■>. 



Mopsella textifornris. 



Melitsea textiformis, Lamarck, M6m. Mus. Ilisf. Nat. i. p. 412 



Lamouroux, Polyp. Jlexibles, p. 4^4, pi. xix. fig. 1. 

 Melithnpa textiformis, M.-Eduwfe & Haime, Hist. Cor. i. p. 201. 



