78 Rev. T. Hincks on the Reproduction of Clavatella, 



The Clavatella-zooid, on the contrary, moves with ease up the 

 perpendicular sides of a glass vessel, the mouth being on the 

 lower side as it walks, while it is quite equal to the Eleutheria 

 as a climber. 



There are a few other minor differences between the two ; but 

 the general resemblance is so great, that we may refer them 

 both (provisionally) to the same genus. 



The Eleutheria of De Quatrefages, therefore, is the reproduc- 

 tive zooid of a Corynoid polype, and probably of a second species 

 of Clavatella. 



It was obtained at the Chausey Islands, off the coast of Nor- 

 mandy, and in rock-pools, so that its habitat is similar to that 

 of its Devon congener. The points on the French and English 

 coasts at which the two species have been found are nearly 

 opposite to one another. I am not without hope that the polype 

 which produces the Eleutheria may yet be discovered on our own 

 teeming western sea-board. 



The reproductive zooids of Clavatella differ from those of any 

 other Hydrozoon with which we are acquainted, inasmuch as 

 they do not exhibit the Medusan structure which characterizes 

 universally the motive buds produced by the other known mem- 

 bers of the class. The sexual bodies closely resemble the ali- 

 mentary polypes, presenting the same essential structure, which, 

 however, is somewhat modified to meet the conditions of a free 

 existence. An efficient locomotive apparatus is superadded, and 

 the long pedunculate body which supports the head and tenta- 

 cles of the alimentary zooid, and secures to it the necessary faci- 

 lities for the capture of food, is suppressed. The homologue of 

 the latter, however, exists in the stem by which the bud is at- 

 tached to the polype, a short piece of which it carries with it 

 after detachment, but which gradually disappears. The repro- 

 ductive zooid of Clavatella is, in fact, a free polype-head, the 

 tentacles of which are furnished with a retractile branch, termi- 

 nating in a suctorial disk, and forming an organ of locomotion. 

 The arms, divested of this appendage, bear an exact resemblance 

 to those of the alimentary polype, even exhibiting the same 

 number of opake-white patches, and in precisely the same posi- 

 tions. The only additional elements besides are the six red 

 spots, situated at the base of the six tentacles, which M. de Qua- 

 trefages has described as eyes. If this view of their function 

 be correct, they would seem to be a very natural adjunct to the 

 provision for a free existence. I confess, however, that in the 

 case of the Clavatella prolifera I have failed to distinguish the 

 structure which M. de Quatrefages describes, and had regarded 

 the supposed eyes as mere pigment-spots *. 



* The following is tho passage from the Meuioire, relating to the eyes : 



