or THE PROTOZOA. NOCTILUCIDA. 385 



possible reproductive apparatus, which I have seen, consisted of a number of 

 granular vesicular bodies of about -g- cnro^^ of an inch in diameter, scattered over 

 the sui'face of the anterior and inferior part of the body." Dr. Webb (op. 

 cit. p. 105) has the following observations on this subject : — " I have never 

 met with a double individual, but on one occasion witnessed the process of 

 di\*ision, T\ithout, however, noting any proof of its connexion with that of 

 fissiparous multiplication. Contractions of the integument took place in such 

 a way as to cut off a globular mass from the body, about one-fourth of the 

 whole. The two portions afterwards retained their form, with a puckered 

 mark at the point of separation. The nucleus was not involved in this ope- 

 ration, which occupied about two hours. 



" It is also a matter of eveiy-day observation, that when the body has 

 been torn and nearly all the contents have been lost, the animal continues to 

 live in a deformed state, if the nucleus and central parts are left together. 

 They acquire a new investment ; or a portion of the original integument 

 gathers up round them, while the ragged shreds are cast off. 



'' When several of these creatiu-es have been kept for some time in still 

 water, it is not unusual to find two of them in apposition ; but I have never 

 discovered any indications of conjunction, and look upon the condition as one 

 of mere adhesion. It may, however, have given rise to the mention of double 

 individuals, as the adhesion is tolerably firm. It may easily be broken up 

 without injury to either animal.'' 



In the Journ. of Micr. Science for 1855, p. 99, is the translation of a paper 

 by Dr. Busch on the structm-e and function of Noctiluca, in which several 

 original observations are given which appear to bear on this question of de- 

 velopment. There is, however, such uncertainty about them, and the want 

 of confirmatory evidence, that we deem it unnecessary to quote them, and must 

 therefore refer our readers to the Joui'nal cited. The fom^th volume of the same 

 excellent periodical (p. 74) contains a translation of a paper by Prof. Miiller, 

 from which it appears that this distinguished naturalist had discovered Nocti- 

 luca in an encysted condition. The account he gives stands thus : — " These 

 encysted bodies constituted the principal limiinous animalcules observed at 

 Messina in the autumn of 1853. Free NoctiluccB at that season were not 

 seen there ; and in 1849 the same kind of encysted bodies were very common 

 at Mce. The cyst is a perfectly transparent, spheiical capsule, with a light - 

 bluish brilliancy at the edge, and appearing like the egg-membrane of some 

 Cnistacea. Within this cyst is lodged a body in all respects resembling the 

 Noctiluca miliaris, except that at this time no vibratile filament can be per- 

 ceived. The Noctiluca-Y\k.Q creature fills the cyst more or less entirely, though 

 occasionally it is much smaller. In this condition the animalcules are lumi- 

 nous without being agitated. When the cysts are examined under the 

 microscope in a small quantity of sea-water, in such a way that during the 

 observation the saline contents are notably increased in consequence of the 

 evaporation, a moment speedily arrives when the Noctilu€a-\ike> body sud- 

 denly contracts itself within its case into a little nodule ; that is to say, it 

 contracts upon the yellowish granular nucleus from which the filamentary 

 strings of the inteiior proceed. I have noticed this vital phenomenon, not 

 on one occasion only, but in many of the encysted animalcules. 



'' The size of the case is usually from 4'" to \"' . But many are far smaller, 

 even down to -yV"- Occasionally also, instead of a Noctiluca, cysts may be 

 observed, containing a yellow nucleus ■^"' in diameter ; and once I noticed 

 a cyst -^"' in size, containing, besides this rounded yeUow nucleus, quite 

 isolated, an extremely minute Noctiluca-Yike body. Of the free Noctilucece 

 taken near Heligoland in the autumn, the smallest were ^"', and the larger 



2c 



