976 SUMMARY OF CURRENT RESEARCHES RELATING TO 



aided by the strong pressure from the extended cuticular surface, which 

 tends to force the pharyngeal fascicle forward." 



Development of fresh-water Peridinese.* — M. J. Danysz comes to the 

 conclusion that there is great uniformity in the developmental history of 

 widely separated genera of Peridinese, and is of opinion that these forms 

 should be associated rather with plants than animals. 



The following seem to be the successive stages : — Active individuals 

 multiply by successive fissions, and become smaller and smaller. Not- 

 withstanding the great differences in the structure of the body and of the 

 nucleus, the process of division is identical in all ; it is always effected 

 along the longitudinal axis of the body, the line of separation being a little 

 oblique to the transverse axis. Phases of multiplication similar to those 

 seen in active forms are to be observed in individuals, which, owing to the 

 liquid which contains them being less fluid than pure water, are in a state 

 of repose. The author thinks that the cause of this phenomenon is purely 

 mechanical. The conditions which M. Danysz looks upon as those of 

 fission were regarded by Stein as states of conjugation. The period of 

 multiplication is followed by that of spore-formation, which has been 

 followed in Gymnodium musci D. and G. glaciale sp. n. 



The spores are spherical bodies quite unlike their mother-cells ; the 

 protoplasm is covered by two membranes, the outer of which is thick, and 

 formed of two layers of different chemical properties, while the inner is 

 delicate and hyaline ; the protoplasm, which is finely granular, contains a 

 large number of various kinds of corpuscles ; these are very small chromo- 

 leucytes which are scattered through the bodies of active individuals and 

 localized into one or several corpuscles in the cysts ; when these are 

 differently coloured, those of distinct colours separate from each other. 

 Drops of oil and of fatty bodies in the solid state, which are probably due 

 to the transformation of starch or granulose, are either found scattered 

 irregularly, or arranged in order in the protoplasm of the spore. The 

 inner lamella of the outer range appear to be pure cellulose, while the 

 outer lamella is probably chitinized cellulose. The inner hyaline layer 

 appears to be the membranous layer of the protoplasm. 



Reproduction of Euglypha.f — Dr. F. Blochmann describes experiments, 

 which supplement Gruber's observations on the division process amongst, 

 shell-bearing fresh-water Ehizopoda, which showed that these forms 

 multiply by a budding process. The bud is covered with shell plates as 

 it is formed, and a division of the nucleus occurs at the same time. 

 Separation usually occurs when the bud has reached the size of the parent ; 

 but Dr. Blochmann observes that, in very many cases, further changes 

 before separation end in the death of the budded off portion, so the pro- 

 cess results in no multiplication of individuals. A drawing back of the 

 protoplasm into the original shell leaves the new one empty of all but 

 the young nucleus, which had been pushed into it. This nucleus remains 

 attached to the base of the new shell, and evidently dies as soon as the 

 protoplasm becomes separated from it. Now either of two things may 

 happen. The shell and dead nucleus may fall off together ; or the dead 

 nucleus may again be drawn into the original shell — a pseudopodium 

 flowing round it, and holding it for a time, but ultimately again extruding 

 it. No change in the individual was noted after this curious phenomenon, 

 which Dr. Blochmann compares to the extrusion of polar bodies from the 

 eggs of Metazoa. He thinks a similar process was mistaken by Jickeli for 



* Comptes Eendus, cr. (1887) pp. 238-40. 



t Morphol. Jahrb., xiii. (1887) pp. 173-83 (1 pi.). 



