FISH BREEDING. 685 



scopist Ehrenburg, who facetiously informs us that each has "two large 

 ventricles." This monster with two large yentricles and a round dozen of 

 stomachs, capable of darting about with the incredible velocity of one- 

 twelfth of an inch in four seconds, having clubbed to death a poor 

 Chlamidimonas, settles into depths profound to gorge the precious morsel, 

 and is lost to view as he passes from the focus of the instrument. 



We will also observe a class of beings which have hitherto defied all 

 our powers of investigation, to determine whether they are animals or 

 plants ! no characteristic at present known has been found sufficient to 

 satisfy both zoologist and botanist. 



It will be observed that a large proportion of the infusorial animalcula 

 and rotatoria are furnished with vibratory cilia, or thread-like appendages, 

 which are differently arranged according to the species ; but all fitted and 

 used to produce currents in the water, for the purpose of wafting within 

 their reach particles of animal or vegetable matter on which they subsist ; 

 thus grazing a great extent of pasture without a change of base. Pritchard 

 remarks : *' The disposition of the bundles or clusters of cilia in Botatoria, 

 and their appearance when in motion, may be considered as one of the 

 most curious and interesting spectacles in the animal creation. Their 

 resemblance to toothed wheels, and their continual revolution, have been 

 most fertile subjects for the exercise of the imagination ; indeed there are 

 few which can excite more astonishment in the beholder.'^ Nor is this 

 wonderful apparatus confined to the microscopic infusoria, but are furnished 

 as an aid to the respiratory organs of animals incapable of motion, as 

 observed in the gills of the oyster and mussel, where they serve to produce 

 powerful currents, which bring aerated water to supply the needs of the 

 immovable animal. Nor does this motion seem to depend immediately on 

 the life of the animal, as their form and motion is best observed some hours 

 after they have been detached from the oyster ; when their movements 

 become more sluggish. The epithelium cells abounding in the mucous 

 membrane of the stomach and lungs of man and other animals, are also 

 fringed with vibratile cilia, which may often be observed in rapid motion 

 some time after the death of the animal ; or when they have been detached 

 from their source by scraping the membrane. 



In reading of an opening or mouth in the shell of a newly-laid egg of 

 the Trout, and the action of the spermatic animalcula as detailed in the 

 preceding article on fish breeding, the query arises whether the membrane 

 lining the egg might not terminate around the edge of the orifice men- 

 tioned, in the form of a fringe of vibratile cilia, with power to create 



