REPORT ON THE ALCYONARIA. xlix 



The polyp whorls arc often separated by wide intervals. Large scales, externally 

 smooth and concave, surround the polyp calj'x, which seems to possess but slight 

 powers of curving inwards towards the axis. The ventral surface of the polyps is some- 

 times strengthened by small scales. The spicules of the ccenenchyma are large roundish 

 scales. 



7. Thouarella, Gray, Cat. Lithophytes Brit. Mus., p. 45, 1870. 



The colony is branched. The branches arise at right angles, usually from three 

 sides of the axis. The polyps are club- or cup-shaped, and are placed on the stem 

 in short ascending spirals, which are usually formed of Lhree polyps. Rarely the 

 polyps arise opposite to one another. The scales are different on the dorso-lateral 

 and on the ventral surfaces of the bilateral polyp calyx. The dorso-lateral scales 

 are strono'ly convex on tlieir iijiper mai'gin, towards which small protuljerances radiate 

 outwards from the centre of each scale. Frequently these protuberances fuse and form 

 elevated ribs, which end in teeth-like projections on the margins of the scales. 

 Sometimes the median rib projects as a long spine. The ventral scales are small, 

 delicate plates, which usually form two longitudinal rows. The new polyp calyces arise 

 on the apices of the twigs. 



8. Amphilaphi-'^, Wright and Studer, Archiv f. Xaturgesch., Jahrg. liii. Bd. i. p. 50. 



The colony is branched in one plane. The club-shaped polyps arise at variable 

 intervals from one another around the circumference of the stem, its branches, and 

 twigs, but for the most part from four different sides of the periphery. The scales 

 of the polyp calyx and of the ccenenchyma are thick, and covered with strong wart- 

 like protuberances, which fuse to form ridges on the calyx scales and end on the 

 margin as spines. The operculum, which consists of eight scales, foinis a low cone. 

 The young polyps are developed at the apices of the twigs. 



9. Plumarella, Gray, Cat. Lithophytes Brit. Mus., 1870, p. 36; Studer, Monatsber. 



d. k. preuss. Akad. d. Wiss. Berlin, 1870, p. 648. 

 The colony is branched in one plane, plume-like. The axis is very calcareous and 

 hard. The polyp calyces are small, cylindrical in form, arising in alternate succession 

 from each side of the axis, usually at relatively great intervals from one another. The 

 polyp calyx scales are thin, cycloid, with a central nucleus. 



10. PrimnoeUa, Gray, Proc. Zool. Soc. Lond., 1857, p. 286. 



The colony is simple, rod-like, rising from a calcareous base. The polyp calyces arise 

 from the sttin in whorls nf from four to twenty at more or less distant intervals from one 



