Hicksonella, a New Gorgonellid Genus. By J. J. Simpson. 691 



In Suberogorgia kollikeri, also, the longitudinal bare strips 

 denote the position of the two longitudinal canals much larger 

 than the others. The same holds true in the case of Lophogorgia 

 lutkeni. 



In all the species so far described the ccenenchyma is moderately 

 thick, and it has been possible to verify these points by means of 

 transverse sections, but unfortunately the extreme thinness and 

 the densely spiculose nature of the ccenenchyma in Calypterinus 

 allmani and Hicksonella have rendered it impossible to determine, 

 so far, whether any main longitudinal nutrient canals exist. Is it 

 not possible, however, that in these species, as in the others cited, 

 the occurrence of a bare tract throughout the entire length of the 

 colony may be an outward manifestation of internal morphological 

 structure, and that it corresponds to the position of a single main 

 longitudinal nutrient canal ? 



If this be so, there exists in Juncellids a complete series from 

 one to four main canals, thus : 



1. Hicksonella sp. . . . One main canal. 



2. Juncella juncea, etc. . . Two main canals. 



3. Juncella trilineata . . Three main canals. 



4. Scirpcaria quadrilineata . Four main canals. 



Other features, however, seem to point to the unilateral sym- 

 metry being of morphological and not of mechanical origin. And 

 in this connexion the spiral nature of the colonies must be con- 

 sidered. It will be seen from the descriptions of the three species 

 given in this paper that two of these are spirally twisted, and also 

 that the spiral arrangement does nor commence at the very base, 

 but at a considerable distance from it. In the third species the 

 colonies are all small, and it is possible that they, later on, might 

 have developed the spiral form. 



An analogous case is seen in several Antipatharia in which the 

 polyps have morphologically a unilateral disposition. In the waters 

 around the Mergui Archipelago and also on the reefs on the East 

 Coast of Africa, we have had occasion to examine a large number 

 of spirally twisted colonies, and in no case was any form of support 

 found. Now in the majority of these cases and also in the larger 

 colony of Hicksonella spiralis examined, if any rigid support existed 

 it must also have been spirally twisted, as will be evident from 

 fig. 1, so that it is extremely improbable that these specimens 

 could have been detached from such a support before being brought 

 to the surface of the water. Even if that were possible and had 

 actually happened, it would, of necessity, have caused considerable 

 damage to the colony. No such evidence of fracture is to be seen 

 on any specimen. 



On the other hand it is difficult to imagine how the spiral effect 

 could be produced by free living animals, such as Crustaceans, 



