NOTES ON NOCTILUCA. 329 



forces its way from the central mass into the radiating pro- 

 cesses, and diatoms and other microscopic organisms may be 

 seen in these processes enclosed in cyst-like dilatations of them 

 extemporaneously formed for their reception at various dis- 

 tances from the central protoplasm. 



I have little doubt that the meridional rod-like ridge 

 described above indicates the course of a canal which opens 

 in a duplicature of the body Avails near one end of the entrance 

 to the atrium. This duplicature of the walls appears to have 

 been noticed by Huxley,^ and is more specially referred to by 

 Webb." It may in certain aspects of the body^be seen stretch- 

 ing from the walls of the atrium to the bifurcation of 

 the rod-like ridge, and would seem to open on the surface 

 between this and the neighbouring end of the opening to the 

 atrium. Its sides are marked by transverse strife. It pro- 

 bably affords an exit for some of the effete residue of diges« 

 tion which may be conveyed to it through the process which 

 extends between the central protoplasm and the meridional 

 ridge. If I have correctly followed Huxley's account it 

 would seem to be in this region that he also would place the 

 probable anal orifice of Noctiluca. It is possible, however, 

 that some of the more bulky insoluble materials may make 

 their way back to the gullet and be then ejected through the 

 mouth. Whether the little depression which is visible in the 

 protoplasmic floor of the gullet can be regarded as a specialised 

 point of entrance or exit I have no evidence to enable me 

 to say. 



Numerous brownish-yellow globules resembling oil drops 

 were frequently seen adhering to the outer surface of the 

 central protoplasm mass, and are probably some of the pro- 

 ducts of digestion which had arrived there by transudation 

 from the interior. 



After the completion of the digestive process and the rejec- 

 tion of the solid residue, the central protoplasm may be 

 occasionally seen distended and greatly vacuolated, and the 

 vacuolae filled with a clear fluid (fig. 8). Clear spherical 

 vacuola3 may also at the same time be seen in the course 

 of the radiating filaments. 



Our knowledge of the phenomena of reproduction and 

 development in Noctiluca is still very imperfect, and I saw 

 very little which seemed capable of throwing additional light 

 upon this subject. No instance of transverse fission occurred 

 in any of the examples examined, nor did I meet with the 

 swarm spores originally described by Busch,^ and afterwards 



* Loc. cit., p. 54. * Loc. cit., p. 103. 



' 'Beobacbt. iib. Anafc. u. Eutwickl. eiuiger wirbellosen. Seethiere.' 



