CRUSTACEA. 



631 



genus Chalimus BURM. containing young Caligi. His conjecture has been 

 confirmed by the observations of FR. MUELLER, vid. Archiv f. Naturgesch. 

 1852, s. 91, Tab. iv. figs. 5, 6. 



Family VI. Argulina. Shell membranous, scutiform, placed 

 upon cephalothorax, extending posteriorly into two wings that 

 receive the body between them. Compound eyes, two. Antennae 

 four, concealed under cephalothorax, short; the anterior biarticu- 

 late, recurved, the posterior quadriarticulate. Kostrum acuminate, 

 situated in front of aperture of mouth. Six pairs of feet, the feet of 

 the first pair being changed in adults into two suctorial acetabula; 

 the feet of the second pair short, with basal joint aculeate, the last 

 eight feet cloven into two oars or pilose cirri. Tail short, bilobed, 

 behind the sixth pair of feet. 



Argulus MUELL. (Characters of the family). 



Sp. Argulus foliaceus JURINE, Monoculus foliaceus L. Fauna Suec. 2044, 

 HERM. Mem. apterol. Tab. vi. fig. n, KOCH in PANZER u. HERRICH- 

 SCHJSFFER Ins. Deutschl. Heft 186, Tab. 20. This little parasitic crusta- 

 cean lives in fresh water, and attaches itself to fishes (especially Gaslerosteus 

 pungitius) and to tadpoles. The suckers which had originally the form of 

 fore-feet, are only developed after the fourth moult. Compare on this 

 species the beautiful memoir of JURINE, the son, in the Ann. du Museum 

 d'Nist. nat. vii. 1806, pp. 431 459, PI. 26, from which the figures of 

 DESMAREST (Crust. PI. 50) are borrowed, and C. VOGT Beitrage zur Natur- 

 gesch. der Schweizer-Crustac. Neue Denkschr. der allg. ScJiweizerischen 

 Gesellsch.f. d. gesammt. Naturwissensch. Bd. vn. 1845, pp. 3 16, Tab. i. 

 figs, i 12. 



ORDER III. Lophyropoda LATR. (Entomostraca EDWARDS). 



Mouth not produced into a rostrum, not suctorial; mandibles 

 suitable for manducation, maxillae lamellose. Feet never more 

 than ten, natatory, not foliaceous, often cloven into two oars, 

 furnished with setae or cilia. A single eye or two eyes, sessile. 



Tuft-footed, or Oar-footed Crustaceans. Most of the known 

 species are from fresh-water, and all are of small size ; their motions 

 are rapid and frequently interrupted. 



Comp. on this order : 



MUELL. Entom. (Entomostraca seu Insecta testacea, quce in A quis Danics 

 et Norveglce reperit, descnpsit et iconibus illustravit O. F. MUELLER, Lipsise 

 et Hauniae, 1785, 4to.) ; JURINE, Hist, des Monocles qui se trouvent aux 

 environs de Geneve, 1820, 4to. av. fig. 



