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



another. The polyp calyces are distinctly bilateral. The calyx scales form longitudinal 

 rows ; an individual scale usually overlaps for half its leugth the adjoining scale. The dorso- 

 lateral surfaces of the calyx are usually covered by two longitudinal rows of scales; the 

 ventral side has small, flat disc-like scales. The shape of the calyx scales is irregularly 

 quadrangular, the nucleus is always excentric, and from it small protuberances radiate 

 outwards. The new polyps arise between the existing w^horls. 



11. Caligorgia, Gray (emend. Studer). 



Callogorgia, Gray, Proc. Zool. Soc. Lond., 1857, p. 286; Bid., 1859, p. 481. 



Calligorgia, Gray, Cat. Lithophytes Brit. Mus., 1870, p. 35. 



Ccdligorgia, Studer, Monatsber. il. k. preuss. Akad. d. Wiss. Berlin, 1878, p. 645. 



The colony is upright, and branched in one plane. The polyp calyces are cylindrical 

 or club-shaped, and occur irregularly distributed upon the stem, but on the branches and 

 twigs in whorls of more than three. The calyx scales call to mind ctenoid fish scales ; 

 they are more or less fan-shaped, with ribs which radiate out from the nucleus, and 

 diverging towards the upper margin of the scale end in projecting teeth. Two species 

 referred by Studer to the genus Narella, viz., Narella modesta and Narella divaricata 

 may be for the present included in this genus. 



Subfamily 4. Primnoidin^. 



The colony is branched in one plane ; the polyps are small and opposite. The spicules 

 are flat, thin scales, which are uniformly disposed over the ccenenchyma and the polyp 

 calyces ; they overlaji one another like the tiles of a house. Opercular scales are not 

 distinctly differentiated, and the opening of the polyp calyx is therefore but imperfectly 

 protected. 



12. Primnoides, Wright and Studer, Archiv f Naturgesch., Jahrg. liii. Bd. i. p. 52. 

 The diagnosis of the subfamily will serve for the genus. 



Family VIII. M u R i c E i D ^E. 



Muricea, Lamoroux, Ehronberg. 



Primnoacex, ililiie-Edwards {pars), Hist. Nat. des Coralliaires, t. ii. p. 138. 



Primnoaeex, Kolliker (jiars), Icones bistiologica;, pt. ii. p. 135. 



Muriceadx (subfamily), Studer, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 1878, p. 649. 



Muriceidx, Verrill, 1883, Bull IMiis. Comp. Zool, vol. xi. p. 30. 



Holaxonia, usually with a horny axis, over which there is an outer layer of variously 

 shaped calcareous spicules in the form of spiny discs or half-spiny spindles, spiny stars. 



