602 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the parts. In the former case, the result is that the organism divides into 

 two ; the process of division is effected in the same way in both forms. 



As is well known, Euglena may be distinguished from Astasia by the 

 possession of this chlorophyll, and to this we must ascribe the differences 

 which are to be observed between the vital functions of these two 

 organisms; these differences are — (1) that the chromatophores present the 

 source of an abundant nutrition by means of inorganic elements, and (2) 

 one of the products is a considerable quantity of mucus which exudes by 

 the walls of the body. 



Thanks to the first circumstance, Euglena appears to be accustomed to 

 this kind of inorganic food to such an extent that deprivation is distinctly 

 felt, though it is not fatal ; in darkness, Euglena, unlike Astasia, does not 

 seem to be able to undergo free division, but invests itself in a solid 

 impermeable cyst. The second circumstance, the abundant secretion of 

 mucus, leads, in ordinary division, to the immobile state, and the formation 

 of complex groups ; two facts which play an extremely important part in 

 the life of the Euglena, and which are, if not the sole, yet the most 

 important cause of the great difference in the numerical propagation of the 

 two forms. Astasia, spending all its life in movement, has but little left 

 wherewith to reproduce itself; Euglena, on the other hand, leads a quieter 

 life. The mucous coverings of Euglena defend it from cold, heat, and 

 evaporation, enemies, and the effects of an insufficient supply of food, while, 

 when they form themselves into a connected mass, the ciliate Infusoria, 

 which prey on them when they are single, are unable to attack them. 

 Astasia, on the other hand, cannot form either colonial groups or united 

 membranes, and so, in the struggle, has one important weapon the less. 



As all these facts are due to the presence in one and the absence from 

 the other of the chromatophores, these appear to be the sole essential 

 character which distinguishes Astasia from Euglena ; the one is an Astasia 

 provided with chromatophores, the other a Euglena devoid of them ; in 

 fact, we may put our present knowledge thus : — If the Chitridise, which 

 glide into the Euglense and first devour the chromatophores, were to leave 

 without doing any other harm, there would be an organism identical with 

 Astasia in all its essential characters and functions. Were this to happen, 

 the Euglena would have to learn to be content with organic nutriment ; 

 indeed, the advantage in the struggle for existence that Astasia now has, is, 

 that it can take assimilable organic nutriment which contains force-stuffs 

 already made. 



New Peridinian.* — M. J. Danysz describes the structure and life- 

 history of a new Peridinian (Gymnodinium mussei n. sp.) found in the Jardin 

 des Plantes. The flattened ellipsoidal form, the absence of cuticular 

 envelope ; the transverse groove dividing the body into two unequal parts, 

 obliterated, however, at the middle on one side ; and the presence of an 

 irregular prominence at this point, bearing the sujierficial, red, ocular spot 

 and the two flagella, are characteristic features. 



The reproduction of G. mussei occurs (a) by means of successive divisions, 

 (6) followed by the formation of spores — the result of the fusion of two 

 individuals of minimum size. During July and August the development 

 of an individual is complete in fifteen days, but in favourable conditions 

 this may be much accelerated. 



Peridinea.f — M. G. Pouchet communicates a fourth contribution to the 

 history of the Peridinea. After a general introduction, in which he dis- 



* Arch. Slav. Biol., iii. (1887) pp. 1-5. 



t Journ. Anat. et Physiol., xxiii. (1887) pp. 87-112 (2 pis.). 



