912 SUBIMAKY OF CURRENT RESEARCHES RELATING TO 



greater transparency was entirely empty, wliile the protoplasm of the 

 other contained two entire nuclei, and another partly broken up into 

 fragments. This process appears to be undoubtedly a kind of copu- 

 lation, though the actual coming together of the two individuals was 

 not observed ; it is evidently no case of division and the only possi- 

 bility is that it might be equivalent to a rejuvenescence ; this objec- 

 tion may, however, be refuted by the observation of the active 

 pseudopodial processes and by the breaking up of one of the nuclei, 

 and also by the fact that it was not the more transparent but the more 

 granular individual which finally retained the whole protoplasm of the 

 two ; moreover in other individuals of the same species the most care- 

 ful search failed to show more than one or two nuclei. It appears 

 therefore that (1) copulation takes place among Ehizopoda as well as 

 among Infusoria ; (2) during the process there is a stage of diminished 

 vital activity in both groups ; (3) as a result of the process there is a 

 breaking up of the nuclei. 



Development of Stylorhynchus longicoUis.* — The results of 

 A. Schneider's researches on the development of this Gregarine, may 

 be thus summed up : 



Stylorhynchus longicoUis passes through most of the stages of its 

 development, and often even acquires the characters of the adult, in the 

 interior of an epithelial cell of the intestinal tract of Blaps. This 

 fact shows that Giard is not justified in drawing a distinction between 

 Gregarines as forms living in cavities where they are free and Psoro- 

 sperms as being intracellular parasites. One and the same epithelial 

 cell may contain a varying number of inhabitants, which may either 

 be separated from one another, or united in groups ; in the latter case 

 they are more or less deformed by the pressure they exert on one 

 another. The parasites may be found between the nucleus and the 

 nuclear membrane. At first they are identical with the forms known 

 as Coccidia, and, in their development, four stages are to be distin- 

 guished ; in the first they are simple cells with a solid nucleus, in the 

 second the nucleus becomes vesicular, in the third they have the form 

 of segmented cells with a nucleus in the proximal segment, and in the 

 fourth they are segmented cells with a nucleus in the distal segment. 



The segmentation of the body, which is at first purely external and 

 superficial, precedes the migration of the nucleus from one to the 

 other pole. The septa in the cell do not appear until after the 

 migration of the nucleus. The cavity in the rostrum corresponds 

 to the position occupied by the nucleus before its migration. The 

 segment first produced is the fixation-apparatus of the adult ; the next 

 to appear is the deutomerite or distal segment, then the protomerite, 

 and then the neck. 



Strictly spuaking, the first segment buds off the rest, and the phe- 

 nomenon of spontaneous mutilation is, morphologically, comparable to 

 the act by which a bud is separated from the mother-cell. In S. longi- 

 cullis development is direct, for there is no alternate generation, or 



* Arch. Zool. Exper, tt Gen,, ii. (1884) pp. 1-36 (1 pL). 



