200 DH. BUSCH, ON NOCTILUCA (MILIARIS?). 



animal moves this sort of prohoscis slowly backwards and forwards. 

 Opinions are much divided as to whether an opening, or sort of mouth, 

 exists in this liilus, or whether the creature is unfurnished with such an 

 organ." 



Though he has not seen it, the author believes there must 

 be an entrance. 



" From the few data," he goes on to say, " afforded by the study of the 

 development of this curious creature, it may, however, be shown that an 

 inversion or invagination takes place in this situation, and consequently 

 that an entrance must exist. 



" As regards the interior of the disc ; in some individuals it was per- 

 fectly emptj^, but in others, several brown bodies existed, as seen in fig. 1/, 

 sometimes of a rounded, sometimes of an oval or hour-glass shape. Occa- 

 sionally they were in such close apposition with the nucleiform body, that 

 the latter appeared to be continued into them ; but they might also be 

 noticed perfectly free in the interior. The structure of these bodies is 

 shown in fig. 8 : it represents a cell with homogeneous walls, and contain- 

 iuo- a large, coarsely granular nucleus. Among numerous perfect Nocti- 

 lucw, some were met with composed apparently of nothing but an empty 

 membrane, and whose true nature could only be recognised from the 

 presence of the iwoboscis. In the interior of these sacs were found minute 

 corpuscles, such as are represented in fig. 2 ; viz., oval cliscs, with a 

 nucleus occupying nearly the whole interior. The colour of these bodies 

 corresponded with that of the minute globular bodies, which were noticed 

 in the interior of the old Noctilucve, but from which they were distin- 

 guished by the homogeneity' of the substance of the nucleus. Occasionally, 

 though more rarely than the above, these sacs contained germs somewhat 

 farther advanced in their development (fig. 3). The most important 

 change apparent in these is the existence of a process as yet obtuse. 

 These bodies occurred more abundantly in the free state, swimming about 

 among the other Noctilucce, than those contained in the saccuU ; and their 

 farther development was observed to take place as follows. The obtuse 

 process becomes pointed, and on its side is formed a minute appendage, 

 arising from the opaque nucleus, and resembling in structure and relations 

 the proboscis of the adult animal (fig. 4). It is thence evident that the 

 nucleus represents the brown nodule in the hilus of the mature Noctiluca, 

 and that the motile filament arises from it. It might now be expected 

 that the round disc simply increased in size, and that the other organs 

 were developed in its interior ; but it would appear that the entire organism 

 is subjected to remarkable transformations before this result is attained to. 

 As the disc increases in size, the pointed process becomes elongated out- 

 wardly (figs. 5 and 6) ; and in its interior appears a structure resembling 

 the ' rod ' which we have described as existing in the Noctiluca ; but the 

 direction of the rod at this time is exactly the reverse of that in which 

 it is placed in the adult animal. For whilst in the latter, starting from 

 the brown nodular body, it stretches towards the periphery of the disc 

 farthest from the nucleus, in the former it projects straight out from it. 



" At the same time also the border of the disc loses its evenness, and 

 acquires angular processes of the same colour and consistence as the disc 

 itself (figs. 5 and 6). Viewing all these figures, it seems most probable 

 that the form of the large animal is develo])ed out of them in the follow- 

 ing way. As the disc continues to grow, the ' rod' must be reverted on 

 itself, and the processes of the disc having at the same time become longer 

 and broader, must close over it and unite. The animal would thus be 

 perfected ; and, upon any other supposition, it is not easy to see how the 



