THE ALCYONARTA OF THE CAPE OF GOOD HOPE AND NATAL. 557 



3. The basal part of the polyp, containing the lowermost part of the stomodseal 

 tube and the mesenterial filaments, is protected externally by a much projecting calyx 

 with numerous red spicules. It was not clear whether the calyx could be retracted 

 or not. 



The following are the dimensions of a fairly expanded polyp : 



1. Length of upper part (crown) from tip of tentacles to base 



of encircling band of spicules, . . . 2 '40 mm. 



2. Breadth of same at middle, . . . 1*50 ,, 



3. Diameter of spread of tentacles, .... 1'20 ,, 



4. Length of median (stomodseal) part, . 1'20 ,, 



5. Breadth of same at middle, . . . 1'45 ,, 



6. Length of calyx, . . . . . . I'OO ,, 



7. Breadth of calyx at middle, . . . 1*25 ,, 



The following are the dimensions of a fairly retracted polyp : 



1. Length of upper part, . ... . . 1'25 mm. 



2. Breadth of upper part, . . 2'60 ,, 



3. Length of median part, . . . . I'lO ,, 



4. Breadth of median part, . . . . 175 ,, 



5. Length of calyx, . . . . . . . I'OO ,, 



Transverse sections through the stomodseal part show that the muscles are very well 

 developed, that the wall of stomodaeum (proper) is thick, and that the siphonoglyphe is 

 provided with cilia. In one of the specimens (P.F. 10,881) female gonads were con- 

 spicuously developed on the lower mesenteries of the polyp, and in the intermesenterial 

 cavities of the stomodeeal region a number of eggs were observed (PI. III. fig. 19). 

 The other specimens did not show gonads. A characteristic feature is that the lower 

 portion of the polyp lies within and is protected by a much projecting calyx, which 

 appears to be more of the nature of an outgrowth of the outer rind than a part of the 

 polyp itself. Sections show that the uppermost part of this outgrowth or calyx 

 surrounds the lower part of the stomodseum, but that the greater portion is occupied by 

 that part of the polyp in which the mesenterial filaments are situated. The walls of 

 this cavity vary in thickness : in the upper part it is one- layered, in the lower part two- 

 layered. The greater part of the polyp can be retracted within this cavity. 



The cavities of the polyps are continued into long canals passing down through the 

 coenenchyma of the trunk. These canals are large, numerous, and conspicuous. The 

 canals are not in direct communication with one another. The canals in the outer part 

 of the trunk are slightly smaller than those of the interior. The outer part of the trunk 

 has a tougher consistency than the centre, and the spicules are more crowded together. 

 Specimen (No. 10,881) showed gonads developed on the walls of the canals of the trunk. 



The other specimens did not show these. 



TEANS. ROY. SOC. EDIN., VOL. XLVII. PART III. (NO. 19). 82 



