THE ALCYONARIA OF THE CAPE OF GOOD HOPE AND NATAL. 569 



The polyps show varied degrees of expansion and contraction, the best expanded 

 showing tentacles and pinnules, the most contracted being withdrawn and covered over 

 by the coenenchyma. On retraction, the tentacles are apparently drawn downwards, 

 but the pinnules are not inverted. A well-expanded polyp extends about 3 mm. above 

 the surface of the coenenchyma, and has a diameter of about 1 mm. The diameter of a 

 fairly contracted polyp extends about 0'35 mm. on the surface of the coenenchyma. 

 The calyx is not well defined. The well-expanded polyps at the margins of the lobes 

 lie closely adjacent to one another ; in the centre of the lobes, however, contracted 

 polyps may be separated by an interval of 1 mm. Some of the better expanded polyps 

 show eight faint, longitudinal lines on the surface. Each tentacle bears at least 9 pairs 

 of pinnules. The polyps themselves have apparently no spicules, though these are 

 aggregated in large numbers at their bases. A fairly contracted polyp has the appear- 

 ance of a swelling with eight lines on its surface, or is merely a papilla without any 

 such differentiation. 



The following points in the internal anatomy may be noted : The muscles are 

 large, and the invaginated ectodermal wall of the stomodseum is thick. In the 

 uppermost part of the polyp, the siphonoglyphe is not well defined, but further 

 down it is wide and possesses numerous cilia. In several polyps, the siphonoglyphe 

 is seen to be situated towards the outside, or, in other words, away from the centre 

 of the coenenchyma. The endodermal layer in the stomodseal part of the polyp is 

 extremely well developed. The mesenterial filaments, when well developed, appear to 

 be grouped in 4 or 5 lobes on each mesentery. The cavity of each polyp is continued 

 into a canal, which passes down through the coenenchyma to near the base of the colony. 

 At the very base, these more or less vertical canals communicate with one another, and 

 expand into others which run horizontally in the lamella-like, encrusting part. 



An interesting feature was the occurrence of female gonads and eggs in the canals 

 of the ccenenchyma, and also more rarely in the part of the exposed polyp containing 

 the mesenterial filaments. The eggs showed nucleus and nucleolus very clearly. As I 

 have only one specimen of this species I am unable to follow up the study of these 

 gonads and eggs. 



The spicules are found in the flat, encrusting, basal part of the colony, and in the 

 coenenchyma at the base of the polyp. I had hesitation in deciding whether the latter 

 spicules belonged properly to the polyps or to the coenenchyma, but sections lead me 

 to think that the spicules of the external coenenchyma are simply more abundant at the 

 base of the polyps. There are no spicules in the internal coenenchyma. The spicules 

 of the encrusting base do not vary to any extent, either in size or shape, from those of the 

 polyp-bearing part. They are in both cases double wheels, and have the following 

 dimensions: From 0'0999 by 0'0729 to 0'12L5 by 0'0837 mm., and from 0'1026 by 

 0'0675 to Q'1215 by 0'0945 mm. The rind of the lobes is hard and compact, but this 

 is due not so much to the spicules as to a fibrous condition. 



This form shows a number of points of resemblance with Alcyunium globulifa-um, 



