REPORT ON THE ALC YON ARIA. 255 



eight more or less distinct longitudinal furrows, which extend sometimes throughout 

 the entire length, sometimes only along the upper portion. The body-wall projects in 

 ridges between them. The mesoderm of the polyp is beset with spicules which are 

 closely apposed to one another and so make the calyx into a rigid tube. 



These spicules are for the most part thick spindles, covered all over with rough 

 warts, and enlarging at one end into a club-like form. Rod-shaped curved spicules also 

 occur, especially in the longitudinal grooves. The retractile portion of the polyps 

 contains either no spicular elements, as in Clavularia crassa, or thin spindles and rods 

 which may extend even into the tentacles. They are usually disposed in eight 

 longitudinal strands, which are then continued into the tentacles. 



Even the oesophageal tube may contain spicules, as for instance in Clavularia 

 frigida, Danielssen. In the colonies united by stolons, the stolons arise from the 

 bottom of the calyces, which become narrowed at their bases and give origin to one 

 or more cylindrical or flat processes from which new jiolyps are budded off. This 

 formation of stolons agrees exactly with that met with in Cornularia. In some species 

 the base of the polyps broadens out into a membrane which unites the individuals 

 together. In this case the base of the calyx gives origin to endodermal tubes, which 

 anastomose on the basal membrane, and thus connect the alimentary cavities of the 

 various polyps. The calyces are always seated upon the stolons or upon the basal 

 membrane, and are never sunk into them as in Anthelia or Sympodium. The polyps 

 usually arise at relatively great intervals from one another. It may happen, however, 

 that two arise close together ; or, as a rare case, one polyp arises at the base of the calyx 

 of another, so as to produce the social condition so well seen in Telesto. But even 

 then the alimentary cavity of the bud is not in direct connection with that of the polyp, 

 being only united to it by fine nutritive canals which ramify from the wall of the calyx. 



The species as yet known are not numerous ; of those provided with stolons 

 Clavularia viridis, Quoy and Gaim., from Vanikoro in the Pacific Ocean, was the first 

 described. Clavularia {Cormdaria, Milne-Edw.) crassa, M.-Edw., from the ]\Iediter- 

 ranean, was described in detail by Kowalevsky and Marion.^ By the same authoi-s a 

 second Mediterranean species was distinguished as Clavularia i^etricola. The species 

 in which the polyps are united by a basal membrane are Clavidaria violacea, Quoy and 

 Gaim., Clavularia rosea, Studer, and the northern forms Clavidaria horealis, Koren 

 and Danielss., Clavidaria arctica, Koren and Danielss., and Clavidaria stormi, 

 Koren and Danielss. As not belonging to the genus Clavularia may be mentioned 

 Clavularia riisei, Duch. et Mich., and Clavidaria prolifera, v. Koch. Both these 

 belong to the genus Telesto, Lamx. 



The species of Clavularia, in which the individuals arc united by stolons, are in 

 habit very like those of Cornularia. On this account Milne-Edwards refers the 



' Ann. Mus. Hist. Nat. de Miirseille, p. 9. 



