Vibrionia.'] infusorial aisttmalcules. 1.75 



force, one end going foremost, and never the other ; raanj^ stray a 

 great way out of the field : these, by getting clear of each other, are 

 the best to observe ; they do not quite keep their foi-m as a stiff 

 spiral, but their foremost end seems to lash about, and to many are 

 seen attached almost invisible but very long fibres. These fibres 

 were in quick undulations, Avhich ran in waves from the spiral to 

 their farthest end. It appears that these fibres cause many of the 

 spirals to entangle together, and thus bring them sooner to a state of 

 rest; thcivfore, the separate ones were best to observe." 



The most recent observations on these creatures, found in the 

 anthers of the C/mra vulgaris and hhjnda, are by M. Thuret, given 

 to the Annal. des Sciences, a valuable translation of which will be 

 foimd in the Annals of Natural History, vol. vii., from which I 

 exti-act the following : — 



" The portion of their body most apparent, appeared like a spirally- 

 rolled thread, of thi'ee to five curves. 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 difference of nature in these portions. At 

 a little distance behind one extremity proceed two bristles, or ten- 

 tacula, 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 

 cilia. Indeed, the part thus furnished with tentacula moves fore- 

 most, drawing after it the rest of the body, which turns about in the 

 water, but always preserves its turriculate form. The incessant agi- 

 tation of these tentacula, and their extreme tenuity, rendered it im- 

 possible to obsei-ve them in the Living animal ; recourse was therefore 

 had to the evaporation of the water, or to the application of a slight 

 tincture of iodine, when the animalcules ceased, their motions 

 became contracted, and their spiral unroUed, when the tentacula 

 were rendered very distinct, from their brown colour. These 

 tentacula were frequently observed to be soldered together, fi'om 

 one-half to one-thii'd of theii- length upwards, but others were also 

 noticed to be cntirelj^ separated down to their bases. A swelling 



