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



Genus Calyptroplwra, Gray {emend.). 



Calyptrophora, Gray, Proc. Zool. Soc. Lond., p. 25, 1866. 



„ Gray, Cat. Lithophytes Brit. Mus., p. 41, 1870. 



„ Studer, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 642, 1878. 



This genus was established in 1866 by Dr. Gray on "a small fragment" from Japan 

 of a Primnoid Alcyonarian. The polyps had been almost all rubbed off from the axis, and 

 the few that remained had been dislocated. As might have been anticipated under 

 these circumstances, the diagnosis of the genus was very incomplete, and although the 

 description of the genus in 1870 was altered from that originally given, and the species 

 described by Pourtales as Primnoa trilepis was included therein, yet the diagnosis was 

 in no way emended, and the description of the axis of the polyps and the spicules is 

 incorrect and misleading. The species from Japan, of which there is no doubt Dr. Gray 

 had an " eroded " specimen before him while writing his descrii^tion of Ccdypti-ophora 

 japonica (this is still in the British Museum), is now, however, to be found in most large 

 collections of Alcyonaria under Dr. Gray's name, and it would, therefore, serve no useful 

 purj^ose to alter the generic or specific name. 



Axis branched, sometimes branches are unilateral, other times irregularly dichotomous. 

 The ccenenchyma of the axis is thin, the spicules are large, irregular in form, tightly 

 fitting over the surface or overlapping. The axis is hard, horny, consisting of bundles 

 of fibrillse penetrated with amorphous calcareous particles, and the surface when bare 

 of ccenenchyma has a wavy iridescent appearance. The basal portion is densely 

 calcareous, with a central fibrous core, and the outer ring is striated. 



The polyps are arranged on the axis in whorls of four, five or more. The body of 

 the polyp is protected by three series of scale-like spicules of great size, of which the 

 second and third series consists each of a single broad and hollowed ring-like scale 

 (annular spicules). Opercular scales, eight in number, closing over the retractile tentacles. 



The spicules of the body of the polyps will be found extremely characteristic of this 

 genus as emended. 



1. Calyptrophora japonica, Gray (Pis. XII., XX. fig. 4). 



Calyptrophora japonica, Gray, loc. cit, p. 25, et loc. cit., p. 41. 

 ,, ,, Studer, loc. cit, p. 642. 



The specimen in the collection, which appears to correspond to Dr. Gray's type, was 

 taken off the Fiji Islands. The basal portion of the axis is present as a dense calcareous 

 knob, about 6 mm. in diameter ; at 70 mm. in height the axis divides into two main 

 branches ; each of these gives origin to a number (sixteen or more) of slender twigs, which 

 are all unilateral, apparently the result of a unilateral dichotomy. The first twig, after 



