DAPHNIAD.E. 71 



The posterior of the two branches is divided, in most 

 of the species, into four articulations, and the anterior 

 into three. Both branches are furnished with several 

 long filaments or setae, which, in some of the species, as 

 the pule, are beautifully feathered, or plumose, and con- 

 sist each of two moveable joints, which augment their 

 flexibility. Swammerdam calls these organs the arms, 

 and describes their motion very particularly, which, he 

 says, is threefold ; rectilinear, up and down, and to each 

 side ; imeqif-aJ, keeping the animal now at the bottom, and 

 then at the top of the water, which sort of motion he 

 compares to the flight of a sparrow ; and gyratory, by 

 which the animal moves itself in a circular manner. 

 De Geer also calls them arms; but M tiller, and most 

 other naturalists after him, call them antennae. Jurine, 

 however, calls them " bras ramifies," and Straus, consi- 

 dering them as the chief or almost only organs of loco- 

 motion, and acting as it were as fins, calls them rami or 

 "rames branchues;" they are, in fact, he says, a first pair 

 of feet, and act as such, as it is by means of these organs 

 alone that the animal moves, the other feet not serving at 

 all for that purpose. 



The eye (t.VIII, f. A, B, c) is a spherical body, furnished 

 with powerful muscles, so arranged as to allow it to pos- 

 sess a semi-rotatory motion upon its centre, and is com- 

 posed of about twenty crystalline lenses, which are limpid, 

 and when isolated are each pear-shaped. Swammerdam 

 asserted that there were two eyes, which seemed to be 

 joined together, and several authors have adopted the 

 same opinion. Schoeffer, however, says there is only one, 

 and Miiller and De Geer repeat this, an opinion which 

 has also been adopted, and proved correct by Straus and 

 Jurine. Eichhorn, as quoted by Straus, mistook the eye 

 for the stomach ! 



The brain, or first ganglion of the nervous system, is 

 situate near the eye, and is composed of two lobes, from 

 the superior anterior commissure of which we see, going 

 off to the eye, the optic nerve. The mouth (t. VIII, f. B) is 



