Excerpta Botanica. 45 



observed the rapid formation of the nucleus in filaments which 

 previously possessed no traces of it. These nuclei have a slight 

 green tinge, probably owing to an optical illusion, and become 

 brown by iodine. They are always affixed [adosses) to the 

 partitions {cloisons). Gradually they become effaced, and the 

 animalcules begin to be distinguished ; indeed, they are fre- 

 quently observable at one extremity, whilst the nuclei remain 

 at the other, even in the same anther and filament. On the 

 complete formation of the animalcules, the partitions of the 

 chambers are indistinguishable, from the confusion arising 

 from the great number of the curves. At each curvature of 

 the animalcule a swelling (black or brilliant, according to the 

 increase or diminution of focal distance) is perceived, doubt- 

 less owing to the optical illusion produced by the greater 

 thickness of the body at these points of flexion. 



The animalcules are at first motionless, and remain for a 

 greater or lesser time in the water before they begin to move 

 and struggle to release themselves from their prison. In this 

 they do not always succeed, although their twisted position 

 attests the eiforts made for disengagement. Those which do 

 succeed escape laterally by a sudden motion, similar to the 

 elasticity of a slackened spring. After this great effort they 

 remain for some time motionless, or if the temperature and 

 season be unfavourable, their motions are slow and soon 

 cease. On the contrary, the animalcules observed at the end 

 of June and beginning of July agitated themselves with ex- 

 treme vivacity, and in such a manner as to leave no doubt of 

 their animality. They rapidly traversed the field of the mi- 

 croscope in different directions, crossing and meeting each 

 other, and deviating from their route, and after employing the 

 greater portion of the day in observation, they were left in si- 

 milar and unrelaxed motions. 



The portion of their body most apparent appeared like a 

 spirally-rolled thread of three to five curves [un fil roule en 

 tirebouchon, formant de S a 5 tours de spire.) They were 

 slightly tinged with green similar to the nuclei, and like them 

 turned brown with iodine ; their two extremities becoming 

 more or less coloured (according to the quantity of iodine 

 employed) than the rest of the body, thus indicating a differ- 

 ence of nature in these portions. At a little distance behind 

 one extremity proceed two bristles or tentacula of excessive 

 tenuity, which the animalcule incessantly agitates with great 

 rapidity. These are probably organs of locomotion similar 

 to the filiform prolongation found in the Infusoria without 

 ciliae. Indeed, the part thus furnished with tentacula moves 



