OF ANIMALCULES. 179 



produced into three spines, and between the two anterior 

 ones plays its bifid tail, by which it attaches itself at plea- 

 sure to any convenient substance in the vicinity of its 

 food, and produces a current towards its mouth by the 

 action of its rotatory organs. I have usually found it in 

 July among confervse. Length, l-80th of an inch : the 

 proportional lengths of the spines and tail vary in different 

 specimens. 



424. Brachionus dentatus. The dentated Brachi- 

 onus is enclosed in a bivalve shell, with each end indented 

 and formed into two pair of teeth, as shewn at figure 

 289. This creature is very active and well defended, as 

 it can withdraw itself entirely within its shell : in 

 addition to the rotatory organs for supplying it with food, 

 I have observed it attached to a stem of confervae, and 

 abrading it with its teeth fixed in the bulbous oesophagus, 

 which, during the operation, oscillates quickly ; the rota- 

 tory cilia at the same time move rapidly, which makes 

 it highly probable that they perform some part connected 

 with the organs of respiration, as their motion seems 

 altogether unnecessary while the creature is feeding in 

 this manner. The most remarkable part of this animal- 

 cule is its bright pink eye attached to the bulb of the 

 manducatory organ, as seen in the sketch. The length 

 of the shell is l-90th of an inch. Found among^ con- 

 fervae in June. 



425. Brachionus mucronatus {Salpina, M. E.) The 

 armed Brachionus is sketched at figure 298, and magni- 



