40S 



ROTIFERA. 



cles. The vascular system is composed of 

 tremulous gill-like organs, and a respiratory 

 spur or tube in some species. Noteus has 

 no eyes, but a large cerebral ganglion ; the 

 other genera have eyes. 



Analysis of the genera. 

 Eyeless, with furcate foot. Noteus. 



One in! Without foot. Anurcea. 

 neck. j Foot furcated. Brachionus. 



Two frontal! gtlif foot _ Pterodina . 

 eyes. j J 



With the exception of Noteus, the genera 

 of this family were known to the older ob- 

 servers. Three species of Anuraea were de- 

 scribed by Miiller in 1776, and Joblot disco- 

 vered the Brachionus pala (fig. 296.) in 1716. 



With 

 eyes. 



large quantities that they render the water 

 turbid in which they exist. 



Doyere has constructed a family which he 

 calls Tardigrades, and which are most properly 

 included in the class of Rotifera. The ani- 

 mals of this family have an elongated body, 

 contractile like that of the Rotifer, with four 

 pairs of short legs, each bearing two pairs of 

 small claws. The alimentary canal is narrow, 

 prolonged into a siphon at its anterior ex- 

 tremity, with an internal maxillary apparatus, 

 moveable, and consisting of a muscular bulb 

 traversed by a straight canal, furnished with 

 horny articulated pieces. Until this family 

 was investigated by Doyere, it was supposed 

 to consist of but one species, the Water-bear 

 ( Wasser-bar) of Eichorn ; but under the name 



Fig. 296. 



Brachionus pala. (After Ehrenberg.} 



, eye ; b, jaws ; c, ovary ; d, d, ova ; e, contractile vesicle ; /, ova attached ; g, g, g, teeth of shell ; h, h, 

 intestinal glands ; i, constriction of alimentary canal ; k, respiratory tube ; I, /, transverse vessels. 



The Pterodina patina was described by Eichorn of Macrobiotus, Arctiscon, and other names, 



in 1775. The genus Brachionus is, of all the which were supposed to be synonymous, it 



Rotifers, the most remarkable for the density appears that several animals were confounded, 



of its lorica. The thickness of this organ pre- for which Doyere proposes the generic terms 



vents their internal structure from being so Emydia, Milnesia, and Macrobiotus. These 



plainly obseived as that of many other genera, animals are found in the same localities as the 



The species of Brachionus often occur in so common Rotifer, and like it possess the 



