580 



DR J. STUART THOMSON ON 



rugosa, Kiikenthal, from the coast of Cape Colony ; C. spicata, May, from Zanzibar ; 

 and C. fungiformis, from the coast of Dar es Salaam. 



My species differs from other species of Capnella in the arrangement of the polyp 

 spicules. which is as shown in the line figure (p. 579). 



Euneplithya thyrsoides, Verr. 

 Nephthya thyrsoidea. Verr. 



Plate III. fig. 20 ; PI. IV. figs. 41 a-e. 



This description is based on six or more specimens. 



The dimensions of two average-sized specimens were as follows : 



The colony consists of a short basal trunk (frequently, slightly expanded in a 

 horizontal direction), which soon becomes divided up into two or more branches on 

 which the polyps are irregularly disposed. These branches may also be subdivided 

 into smaller lobes. The number of polyps in the colony varies ; in a larger colony, 

 there are as many as 50 to 70. The number of polyps on the branches also varies ; 

 on some branches there are 5, on others 10 to 13 polyps. Near the trunk, a few 

 young polyps appear to arise singly without any grouping into lobes. Some polyps 

 are curved inwards towards the centre of the lobes, while others, and those fewer, are 

 directed outwards at an angle. The polyps are apparently not retractile, but the 

 tentacles are retractile within the stomodseal part. The polyps are well provided with 

 spicules, mostly long spindles, which are arranged in eight longitudinal bands. The 

 eight longitudinal bands are, however, connected with one another by intervening 

 spicules, and terminate apically in such a manner as to protect the retracted tentacles. 

 Towards the base of the polyp, the longitudinal bands of spicules run into one another, 

 and form a more or less encircling ring of spindles. A calyx is apparently not 

 differentiated, but the apex of the polyp is expanded into a crown. 



The spicules project from the surface of the polyp, in the manner shown in VERRILL'S 

 figure. One also finds that some of the spicules are similar to that shown in VERRILL'S 

 figure. In transverse sections, a few cavities were seen in the upper part of the wall 



