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NOTES AND MEMORANDA. 
The Gemmiparons and Fissiparous Fepjrodiiction of the Nociilnciv 
(Noctiluca miliaris, Suriray). — I sum up in these few lines the follow- 
ing facts, not hitherto pointed out, or imperfectly known, which I shall 
elsewhere describe in detail with others already observed, in a memoir 
about to be published. 
The disappearance of the tentacle, of the basilar tooth, of the 
flagellum, and of the infundibular furrow-like dejDression of the 
Noctilucse before their reproduction, has been noticed by Bright well 
(1857), as vrell as by Cienkowski (1871). 1 have proved that this dis- 
appearance is constant, and not accidental before fission, and that it 
takes place by atrophy properly so called, and not by retraction of the 
tentacle into the interior of the body. I have besides been able to 
follow the phases of the obliteration of the buccal slit, as the pre- 
cursory phenomenon of gemmation. Before fission, this obliteration 
does not take place. The flagellum and the tentacle only fall off. 
The buccal obliteration brings the Noctilucae to the condition of a 
cell properly so called, closed on all sides, spherical, provided with a 
proper wall, represented by the envelope of the animal, and with well- 
known sarcodic contents, with a nucleus without nucleolus, also 
spherical. But there is here nothing to be compared with the en- 
cystment preceding the reproduction of different infusoria (Euglence, 
&c.). 
Far from disappearing before the formation of the gemmas, as has 
been said and figured by Cienkowski, the nucleus of these unicellular 
adult animals of • 3 mm. to 6 mm. diameter plays a direct and im- 
portant part in the constitution of the contents of each gemma, as 
also does the yellowish substance of the cellular body which surrounds 
it ; the cellular wall of the animal rises in a conoidai projection to 
form directly that of each gemma. 
One individual with another, there are produced from 256 to 512 
gemmae, by gradual bisegmentation of the nucleus and of the cellular 
body, with a corresponding production of as many projections or 
gemmfe of the cell- wall, as fills one of the nucleo-cellular segments 
resulting from this bisegmentation. The total duration of these 
})henomena is from ten to twelve hours in a temperature of 12° to 18° 
in April and May. 
The following are the phases of each division of the nucleus in 
this segmentation ; it is lengthened into a cylinder, blunt at each end, 
and becomes very finely granulated, instead of remaining homo- 
geneous. Immediately after, it becomes very finely striated longi- 
tudinally ; the striae are distinct, and evidently result from the juxtii- 
position of very thin colourless filaments, which compression shows 
to be soft and flexible. This fibrillar production, following the greater 
axis of the nucleus, is a constant fact in the fission of the nucleus of 
plants and animals, as Auerbach, Strasbiirger, Biitschli, and E. Van 
Beneden have successively proved. About ten minutes later, the two 
extremities of the nucleus which had remained granulated, become 
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