18 



Fonnnimfeni are enclosed liy the pinnules, they must li;ive entered \vliile the polyp 

 was expanded. The absence of food in the coelentera of most Alcyonarians and the 

 free [iient presence of zoochlorellse point to the fact that many Alcyouaria a ie symbiotic 

 organisms, but the fact we have noticed suggests that some have the power of assimi- 

 lating food from other sources. 



Spicules. 



The great majority of the spicules are arranged irregularly so as to form a 

 dense felt-work on the surface of the canals, giving consistency and rigidity to the 

 whole colony ; but many are also embedded in the mesogloea. On several parts of 

 the colony, however, the arrangement is particularly regular, e.g. on the expanded 

 disc of the verruca, on the protective prolongations of the wall of the anthocodia, 

 and also on the tentacles, where in all cases the arrangement is biserial. 



All are irregularly echinate, while many may be called warty. The spines 

 vary greatly in form and size, some sharp and triangular .standing at right angles 

 to the spicules, others hooked and thorn-like, while others are truncated. They 

 are, for the most part, simple, but compound forms are not infrequent. No type, 

 however, can be said to be characteristic of any particular part of the colony. 



The spicules consist chiefly of straight and curved spiny spindles, some 

 approaching the " scaphoid " form so characteristic of the genus Gorgonia, thus 

 showing convergence in another direction. Other forms are single clubs and clubs 

 with a curved termination, resembling "hockey-clubs." 



In the decalcified sections an organic residue was to be seen in the spicule 

 cavities in the mesoglcea, and an examination of the smaller and more transparent 

 spicules showed that there was an organic axis with branches which passed out 

 into the spiny projections. 



It is interesting to note that the same has been recorded by Bourne for 

 Lemnalia, the genus most closely related to our form. 



The following measurements of spicules in millimetres were taken : 



a. Transparent spicules of the outer wall of the trunk. 



Straight spindles, 0'85 x 0'03 ; 075 x 0'04. 

 Curved spindles, 07xOD25 ; 075x0'03. 



b. Transparent spicules of the partition walls. 



These show a greater preponderance of straight forms and bear 



more compound spines. 

 Spindles, 0'85x0'05. 

 Single clubs, 07x0'03. 



c. Transparent and pale yellow spicules of the disc-like expanded portion 



of the verruca. 

 On the whole these are smaller than the two preceding groups and 



hardly so spinose. 

 Spindles, 0-G5xO'02; O'GxO'Ol. 



