THE ALCYONAK1A OF THE CAPE OF GOOD HOPE AND NATAL. 551 



In the single specimen upon which this description is based, only one polyp was 

 sufficiently expanded to show the tentacles completely extended. It possessed the 

 following dimensions : Length of entire polyp including calyx, 12 mm. ; length of 

 crown and tentacles, 5 '3 mm. ; diameter of spread of tentacles about 6 mm. ; length of 

 stomodseal part, 4'6 mm. ; length of part containing the mesenterial filaments, 7'2 mm. ; 

 length of calyx, 4 mm. ; diameter of calyx, 4 mm. The measurements of a polyp, the 

 tentacles of which were partially retracted, were in the mounted condition as follows : - 

 Length of polyp including calyx, 11 mm. ; length from apex of stomodseum to base of 

 calyx, 9 '5 mm. ; length of stomodseum, 3 '8 mm. ; length of part containing the mes- 

 enterial filaments, 3 '2 mm. ; length of calyx. 3 mm. 



The polyps were well preserved, and thus their structure was readily ascertained. 

 The general form of the polyp is that of a more or less octagonal tube, which expands 

 at the apex into a crown and eight tentacles, and at the base into a wider portion, 

 the calyx.* 



The polyp is differentiated into the following parts : 



1. The crown, consisting of the tentacles and adjacent parts. This region is pro- 

 vided with spicules in the form of long spindles, red and yellow in colour. These 

 spicules are arranged en chevron on the tentacles in eight triangular stripes, and 

 around the base of the latter they form a ring. These triangular stripes of spicules 

 are pointed apically. In each tentacle, there are about eighteen pinnules which have 

 the nematocysts arranged in about eight rings or zones transverse to the long axis. 



2. The stomodfeal region. This shows spicules of two kinds : (a) long spindles 

 externally, and (b) short, broad, spinous spindles internally in the walls of the stomo- 

 dseum itself. Spicules of the latter shape also apparently form a ring round the basal 

 opening of the stomodseum. The spicules within the stomodseal wall (proper) are 

 arranged so that in the periphery their long axes are perpendicular to the longitudinal 

 wall ; internally, they have their long axes parallel to that layer. 



3. The part of the polyp containing the mesenterial filaments which has few spicules. 



4. The calyx. This is strengthened by numerous small spicules, which are 

 arranged en chevron in eight triangular bands or stripes resembling the distribution of 

 spicules on the tentacular region. 



The tentacles, and even the pinnules, possess minute, yellow, irregular spicules 

 measuring 0'085 mm. in length by 0'165 mm. in breadth. Transverse sections through 

 the stomodseal portion of the polyp show the muscles arranged on the mesenteries in the 

 manner characteristic of Alcyonaria, but the muscles in this species are feebly developed. 

 The siphonoglyphe or sulcus shows the presence of cilia very clearly. The cavities of 

 the polyps are directly continued into long canals which pass down through the 

 ccenenchyma to the base of the trunk. The central part of the trunk is of much softer 

 consistency than the more external part, being almost gelatinous. The rind of the 



* I have retained the use of the term calyx throughout this work, although I am aware that another term has 

 been extensively adopted. 



