36 ON THE ANIMALCULiE OCCURRING IN A DROP OF WATER. 



genera, divided among eight families, out of the whole twenty-two. In the 

 Eotifera amounting to five species, representing five genera, and four families 

 out of eight into which the Rotifera are divided; and in addition, as a make 

 weight, I have thrown in one Entomostracan, making in all twenty minute 

 creatures, some of them only the representatives of several hundred others of 

 the same kind existing in the one drop; all endowed with life, some of them 

 highly organized; all of them capable of entering into all the enjoyments of 

 their little world, and each performing the part assigned to it by its Almighty 

 Creator. It is difficult to imagine anything more nearly approaching infinity 

 in numbers, than when one attempts to compute the probable number of 

 indi\'idual Infusoria in even a limited space — even a single pond; what then 

 must be the overwhelming total existing in the whole world? No portion of 

 the earth or ocean indeed, would seem to be destitute of living subjects for the 

 microscope; and much may be learned even in situations which would, at first 

 sight, appear to forbid all idea of the existence of even such minute, though 

 interesting creatures. The following remarks of the celebrated Ehrenberg 

 will assist in illustrating my meaning: — "Not only in the polar regions is 

 there an uninterrupted development of active microscopic life, where larger 

 animals can no longer exist; but we find that the microscopic animals 

 collected in the antarctic expedition of Captain James Ross, exhibit a remark- 

 able abundance of unknown and often most beautiful forms. Even in the 

 residuum obtained from the melted ice, swimming about in round fragments 

 in the latitude of 70° 10, there were found upwards of fifty species of 

 silicious-shelled Polygastrica and coscinodiscce, with their green ovaries, and 

 therefore living and able to resist the extreme severity of the cold. In the 

 Gulf of Erebus sixty-eight silicious-shelled Polygastriea and Phytolitharia, and 

 only one calcareous-shelled Polythalamia were brought up by the lead sunk to 

 a depth of from one thousand two hundred and forty-two, to one thousand 

 six hundred and twenty feet." * 



These remarks of Ehrenberg's shew a profusion of minute living beings to 

 exist in even the most inhospitable sea, but they give no idea of the enormous 

 nmltitudes of the remains of the shelled Animalculae Avhich are found in 

 certain localities. At Richmond, in Virginia, a bed formed entirely of these 

 minute forms exists, which is some sixteen feet thick, and extends, I believe, 

 over some hundred square miles of surface; each cubic inch of this contains 

 the remains of many millions of Animalculae, probably far outnumbering the 

 whole human population of the world. In our own country some similar, but 

 far more limited deposits exist; one at Dolgelly, in Wales, which I have had 

 an opportunity of examining, is entirely composed of minute organic remains, 

 but is confined to a small number of species. Having a considerable quantity 

 of this deposit, I shall be happy to supply any microscopist with some for 

 examination. Recent silicious-shelled Infusoria also exist in very large numbers 



♦ See Ehrenberg's treatise "Ueber das kleinste Leber in Ocean," read before the Academy cf 

 Scieuce, at Berlin, May 9th., 1844. 



