180 NATURAL HISTORY 



fied : it is ratlier larger than the preceding (see Book III.) 

 Found in running springs in summer. 



426. Brach TONUS uncinatas {Co/urus, E. — Colurella, 

 Bory.) — The hooked Brachionus is shewn at figure 297, 

 which affords an edge view, magnified. Tiie shell is 

 bivalve, and of an oval form, pointed at the base : this 

 the animalcule can open at pleasure, and thrust out its 

 simple rotatory organ : its tail is jointed, and terminated 

 by two bristles. Length, l-500th of an inch. 



427. Brachionus cirratus. — The rough-shell Animal- 

 cule, shewn at figure 294, is rather larger than the pre- 

 ceding : it is little known. Midler found it in clear 

 water in the spring. 



428. Brachionus j9a5sw5 is a curious little creature, 

 with two long bristles in front, like the antennae of an 

 insect : it is shewn at figure 286. 



429. Brachionus quadratus, — The scpi are-shelled Ani- 

 malcule, shewn at figure 288, has two rotatory organs 

 seen issuing from the apex of the shell, and two spines 

 from the lower corners ; it has no tail. 



430. Brachionus impressus. — This animalcule, am- 

 plified at figure 287, has a double rotatory organ, which 

 it can withdraw : its tail is long and flexible. Found 

 in stagnant water. 



431. Brachionus urceolaris, {Brachionus, E.) — This 

 creature is shewn at figure 296, vi^ith its rotatory organs 

 and vibrating cilia thrust out : its entire length is l-50th 

 of an inch, the shell being about half that measure : this is 



