Zoology, 3S9 



nity of Blackheath, Kent, a species of J/ydra is very abun- 

 dant; and may be observed, when the water is clear, spreading 

 its reddish tentacula over the mud beneath which its body is. 

 concealed. The tentacula are very sensitive ; for, the instant 

 that the water is agitated, or even touched, they are with^ 

 drawn rapidly within the mud. When taken up, and placed 

 in a glass with water, these zoophytes afford an interesting 

 subject of observation for the young naturalist. {News- 

 paper, 1828.) 



Ififusory Animalcules, — The German naturalist, Professor 

 Ehrenberg has been for years prosecuting researches on these 

 beings, and has discovered wonders on wonders. Meredith 

 Gairdner, M.D., in a late visit to Berlin, cultivated the ac- 

 quaintance of Ehrenberg, who explained to him fully, by pre- 

 lections and the exhibition of the animals (in particular, the 

 anatomy of the Vorticella citrina Miill., Rotifer vulgaris of 

 Schrank, and Hydatina senta), his important discoveries and 

 views. Of all these Dr. Gairdner gives, in a masterly style, 

 an " Analysis," in Jameson's ^Edinburgh New Philosophical 

 Journal for October, 1831, and January, 1832. Dr. Gaird? 

 ner considers Professor Ehrenberg's discoveries " on the 

 structure and functions of the animals, commonly classed 

 under the denomination of Infusoria," as forming an epoch 

 in the science of phytozoology. He remarks, " I fancy my 

 reader to pause at the mention of structure and functions in 

 animals, the discovery of whose existence merely has been 

 hitherto deemed the ultimatum of zoological research, and 

 regarding which the sum total of our knowledge has been 

 hitherto confined to a few details on their external forms and 

 active motions ; yet, in the midst of their transparent tissues, 

 Dr. Ehrenberg has, by a peculiarly ingenious method of 

 observation, developed a highly complicated oj'ganisation, 

 which, with those who arrange the animal kingdom in a 

 linear series, will remove them far from the extremity of the 

 scale. The existence of a digestive, muscular, and generative 

 apparatus is established beyond a doubt : and organs have 

 been also discovered which bear great analogy with the 

 vascular and nervous systems. The great changes which 

 these facts must make in the systematic distribution of these 

 animals are obvious. Nay, from some circumstances, we 

 are inclined to believe that future observations may place 

 these microscopic creations in a parallel order with their 

 more apparent prototypes, and with not less varied and 

 interesting gradations of structure." Dr. Gairdner, in pro- 

 ceeding to exhibit the achievements of Dr. Ehrenberg, 

 divides his subject into these heads: — 1st, The History of 



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