Miscellaneous. 263 



of origin of the zoospores which are found in great numbers in the 

 encysted Noctilucce. 



The encysted Noctilucce, which are met with at all periods of the 

 year at the same time with individuals of normal organization, 

 present the appearance of spherical vesicles, having neither the de- 

 pression at the bottom of which the mouth is situated, nor the tentacle, 

 nor the tooth, but always possessing the nucleus and the streaks of 

 protoplasm. 



Individuals are met with showing transitions between the normal 

 Noctilucce, and these vesicles, deprived of many of the characteristic 

 organs of the species. The tentacle may disappear in a Noctilucce by 

 its being drawn in ; it may also become completely detached in Noc- 

 tilucce which are becoming united. The buccal depression may also 

 become effaced in consequence of the approximation and amalga- 

 mation of the projections which border it. 



The zoospores originate at the surface of these encysted Noctilucce 

 by a development of tubercular prominences, which afterwards be- 

 come constricted at their base and finally separate and swim away by 

 means of a long cilium. 



First of all, four of these buds are produced at the surface (perhaps 

 originally only two). They divide and become in a manner segmented 

 and increase in number until they form a sort of superficial disk. 

 While this phenomenon is going on, the protoplasm presses towards 

 the side of the buds, leaving the other parts of the vesicle. 



The zoospores at the moment of their becoming detached are 

 formed of an inflated hood, covering a flattened oval vesicle containing 

 a nucleus. To the sides of this vesicle is applied a prolongation which 

 is connected on the one hand with the hood, and terminates in a fine 

 point. In one of the angles formed by the union of the prolongation 

 a long cilium is inserted. In many cases also an immovable cylin- 

 drical appendage starts from the hood and extends in the direction 

 of the base of the vesicle. 



M. Cienkowski was unable to keep these zoospores living for more 

 than 24-28 hours, and consequently did not witness their transfor- 

 mation into Noctilucce. 



Besides these zoospores, which may be regarded as representing 

 the normal form, there may be found, attached to the surface of the 

 Noctilucce by a short slender peduncle, vesicles which are often fur- 

 nished with a cilium, a short appendage, an aculeus, and a nucleus 

 sending some protoplasmic filaments to the periphery. These bodies, 

 which have more resemblance than the former to complete Noctilucce, 

 may become detached and move in the water. Their further fate is 

 still unknown. 



The production of the zoospores in the Noctilucce seems to be in re- 

 lation with copulation ; this copulation may take place between en- 

 cysted or non-encysted individuals. The encysted individuals become 

 united by the points which are nearest the nuclei. After a contact of 

 one or two hours, one or several small apertures are seen at the spot 

 where the union has taken place ; and through these the filaments 

 of the protoplasm combine. The amount of perforation increases, and 



