Reproduction o/Euglyplia alveolata, Duj. 35 



the other view. In fact tliere is not much use in testing* the 

 extant instances for this purpose, as usually some special 

 mode of increase connected with the conjugation was observed, 

 although not with certainty. In one instance, however, such 

 a special kind of multiplication after an undoubted conjugation 

 seemed to be very probable, namely in Arcella vulgaris, 

 Ehrbg., according to Biitschli's observations *. In this it 

 was observed that in two out of three conjugated ArcellcB 

 amoeboid offshoots were produced in great numbers after the 

 dissolution of the conjugation f. 



In my subject I have hitherto observed nothing of the kind, 

 although I examined numerous animals united in pairs and 

 several together, both living and in stained preparations. 



The proof here adduced of true copulation in EagJypha, in 

 which from two normal individuals a single animal agreeing 

 with them in structure but exceeding them in size is produced, 

 i?, however, of importance. I rejoice that in this way I have 

 made the first step towards the confirmation of the supposition 

 expressed by Biitschli in his work on the Protozoa, that, as 

 in the other Protozoa, so also in the Rhizopoda, the processes 

 of copulation and conjugation might have assigned to them 

 an important part in reproduction. 



In the case of shelled Rhizppods, so far as I know, an 

 actual copulation has never previously been demonstrated, 

 although it is sufficiently well known in the nearly allied 

 Heliozoa. 



Finally, it may further be indicated that in the process of 

 copulation in Euglgpha alveolata we cannot overlook a certain 

 resemblance to the formation of axospores in the Diatomacere. 

 Although, as is to be expected, future investigation-; will 

 demonstrate the wider diffusion of conjugation and copulation 

 in the Rhizopoda, we may nevertheless already say with con- 

 siderable certainty that they will never occur with the same 

 regularity as in many Flagellata and Infusoria, but that they 

 will always be rather occasional phenomena, the importance 

 of which, however, muKt not on that acc(junt be underesti- 

 mated, as in any case they certainly are the first commence- 

 ment of processes to which, in the life of animals in general, 

 an extraordinarily great, although still by no means clear, 

 significance belongs. 



* Arcli. fiir mikr. Anat. Bd. xi. pp. 459-4G7 (1874). 



t I have convinced myself of the occurrence of conjugation in Arcella. 

 In a vessel which contained enormous quantities of Arcella I found by 

 no means unfrequently two animals with perfectly similar deep brown 

 shells united, wliile the pairs produced by division, which were present 

 in abundance, were readily recognized by the nearly colourless shell of 

 one otlshoot. 



3* 



