Royal Physical Society. 281 



stage of the process, to a mere line of brown granular matter 

 occupying the axis of the capsule, in Clava the endoderm is 

 gradually withdrawn from the capsule altogether, and the ca- 

 vity of the latter at last contains spermatozoa alone. The 

 spermatozoa of Clava, which are very large and active, are 

 discharged from the summit of the spermsac. The ectoderm 

 of both ovaries and spermsacs contains the larger thread-cells 

 in great numbers. 



9. The existence of spermatozoa in the reproductive capsules 

 of Clava, a fact unnoticed by Johnston, was discovered by Ratke 

 in 1844, that of ova by Rudolf Wagner in 1836, but neither 

 of these philosophers fully recognised the dioecious character 

 of this animal. Van Beneden also described Clava in 1844, 

 and figured the male capsule, which he mistook for an entire 

 ovum. Van der Hoeven, in his recent work already cited, ra- 

 ther loosely states that the propagation of this zoophyte is ef- 

 fected by buds which contain ova or spermatozoa, and which 

 occasionally detach themselves from the stem on which they are 

 developed, swim freely about, and resemble small medusse. He 

 gives no authority for such an opinion, and he has probably 

 classed with Clava a number of small clavate polyps with fili- 

 form tentacles, such as the Podocoryne of Sars, the Coryne 

 fritillaria of Steenstrup, and the Zoophyte described at a late 

 meeting of this Society by Mr Peach. There also exist a num- 

 ber of undescribed Tubularian Zoophytes, some exceedingly 

 minute, passing upwards through Clava, Coryne, and Euden- 

 drium, to Tubularia, some of which give off free Medusae. 



Eudendrium. 



10. The two new species of this Zoophyte I now describe can 

 lay claim to none of the arborescent beauty which has gained 

 for this genus the name of Eudendrium. So insignificant are 

 they, indeed, that they are easily overlooked, even when care- 

 fully sought for. The first species, to which I have given the 

 name of Eudendrium pusillum, is found growing on many Ser- 

 tularians and on the back and legs of the Spider-crab, in which 

 last situation it sometimes occurs in great profusion. It is ad- 

 herent to these bodies by a creeping tubular corallum inclosing 

 a filiform polypary. From this creeping fibre stems arise at 



