18 BRITISH ENTOMOSTRACA. 



varying from eleven pairs to sixty in number ; articula- 

 tions foliaceous and branchiform, being chiefly adapted 

 for respiration and not for locomotion ; eyes, generally 

 two, but sometimes three, in some situated at the extre- 

 mity of moveable pedicles ; antennae, sometimes only one 

 pair, but usually two, generally small, and not fitted for 

 assisting the animal in swimming ; mandibles for the 

 most part without palpi. 



Family 1— APODID^. 



Apus, if. Echmrcis, Hist. Nat. Crust., iii, 856, et auctorum. 

 PHYLLoroDA, Lecicli, Edui. Encyclop., vii, art. Crustaceology. 

 Apodid.e, Burmelster, Organization of Trilobites, 34. 



Character. — Antennae one pair, short and styliform ; 

 eyes three, sessile ; feet, sixty pairs, all branchial ; nearly 

 the whole body covered by a large shield-formed carapace ; 

 body composed of numerous rings or joints, 



Biblioc/rapJdcal History. — The first noticewe find taken 

 of any species of the genus Apus, is by Jacob Frisch, in 

 his ' Insecten in Deutschland,' torn, x, published at Berlin, 

 in 1732. He there gives a figure and description of an 

 insect, which he calls "vom Floss-fussigen seewurm mit 

 dem Schild." A specimen, he informs us, w^as sent to 

 him, well preserved in spirits, from Dantzic, by Klein, 

 who was then secretary of state. In this notice he indi- 

 cates, though rather vaguely, the use of the w^ord Apus, 

 — a name which has since been given to the genus, and 

 by which it is now known. Soon after this, Klein sent a 

 short notice, with a tolerable figure of the same insect, in 

 a letter to Sir Hans Sloanc, which was published in the 

 'Philosophical Transactions' for 1738. In this letter he 

 says that it was found at Uderwanga, in East Prussia, 

 amongst fresh- water crayfish, and that, from the great 

 number of its legs and their extreme mobility, he was 

 induced to call it the Scolopendra aquatica scutata. " As 

 long as the insect lives," he says, " so long does it continue 



