70 CLAVATELLIDJE. 



Genus CLAVATELLA, Hinclcs. 



Der. Diminutive of Clava, a club. 



GENERIC CHARACTER. Stems simple and very short, 

 rising from a creeping filiform stolon, the whole invested by 

 a polypary ; polypites borne on the summit of the stems, 

 with a single verticil of capitate tentacula round the base of 

 the proboscis. 



Gonozooids ambulatory, developed in clusters on the lower 

 portion of the body of the polypite, not enclosed in an in- 

 vesting sac (ectothcca). Umbrella wanting; radiating 

 canals 6 or (occasionally] 4 ; marginal tentacles bifurcate, 

 the outer branch capitate, the inner clavate and terminating 

 in a suctorial disk ; an ocellus at the base of each tentacle. 



CLAVATELLA is nearly related to the Eleutheria of De 

 Quatrefages, at least so far as the free zooid is concerned. 

 The polypites of the latter genus have not yet been dis- 

 covered. They are probably extremely minute, like those 

 of Clavatella, which had escaped detection until very re- 

 cently, though widely and abundantly distributed. 



These are the only genera at present known in which 

 the gonozooids are ambulatory. That of Clavatella is a 

 pretty agile walker and climber, at one time using its suc- 

 torial disks as feet, and moving with ease even up the per- 

 pendicular sides of a glass vessel, at another employing 

 them as hands, and climbing amongst the branches of the 

 seaweed. That of Eleutheria, on the contrary, seems to 

 be chiefly scaiisorial in its habits. Both the branches of 

 its tentacles are surmounted by the globular heads, armed 

 with thread-cells ; the special locomotive organ is wanting; 

 and we are not surprised, therefore, to read in M. de 

 Quatref ages' s interesting 'Memoire' that it drags itself 

 with difficulty over a smooth surface, but displays con- 



