90 Dr. P. Cohn on the Development and Propagation 



these structures, to which Al. Braun had already directed atten- 

 tion, under the name of pseudo-gonidia, are remnants of the cell- 

 contents, unconverted into stick-shaped corpuscles, but which 

 have nevertheless acquired a power of independent motion : 

 perhaps they owe their origin to the fusion of a number of the cor- 

 puscles. I likewise sometimes found similar moving globes in the 

 sporangial cells, mingled with the spores, and they appeared to 

 have been formed simultaneously with the latter, out of the cell- 

 contents. These are distinct from other abnormal, cell-like struc- 

 tures in the Spharoplea-ceih, some of which have a power of 

 motion, as also from the parasitic Infusoria (e. g. Trachelius tri- 

 chophorus) which make their way into the interior of the cells 

 through the orifices ; the former are very remarkable and 

 varied ; but I reserve a special examination of them for another 

 occasion. 



The corpuscles which ^ swarm' out from the last-described 

 cells of the >^A<«rojo/(?«-filaments are elongated, bacilliform, and 

 mostly 2 Jo of ^ liiie or more in length ; their form reminds 

 one of certain slender Curculionidse. The posterior extremity 

 is somewhat expanded, often spread out flat and of a yellow 

 colour; one or more granules may often be distinguished in its 

 interior; the anterior extremity runs out into a long narrow 

 colourless beak, bearing at its end two long cilia, which are 

 rendered clearly visible when the corpuscles are killed with 

 iodine. These corpuscles differ strikingly therefore from the 

 spermatozoids of Vaucheria discovered by Pringsheim, and which 

 I have quite recently likewise had the good fortune to observe ; 

 as also from the spermatozoids of the Fucoidese described by 

 Thuret — whatever resemblance may exist in other respects — by 

 the position of the two cilia; and they resemble herein many 

 * swarming-spores ' of Algae, especially those denominated micro- 

 gonidia, with which they are intimately connected in morpho- 

 logical respects. 



The movement of the bacilliform corpuscles in Sphceroplea is 

 characteristic : when the energy is weak they oscillate, as if feel- 

 ing about with the beaks ; when the motion is more active they 

 rotate on their transverse axis, like a stick fastened in the centre 

 and rotated around this ; their movement is distingushed by this 

 from that of true ' swarming-spores,' which rotate on their lon- 

 gitudinal axis. Sometimes the corpuscles rotate upon themselves 

 without moving from one spot, like a cat round its tail ; but they 

 mostly dart off in cycloids, frequently advancing with jerks and 

 springs; more rarely they screw themselves straight onwards. 

 A tendency to seek the light is indicated by their readily col- 

 lecting at the side of the drop of water next to the window. 



Not only did the external resemblance of these corpuscles to 



