122 THE VOYAGE OF H.M.S. CHALLENGER. 



a brief review of the systems successively adopted for their classification. The sixth 

 chapter, containing this review, is admirably illustrated by five " tableaux synoptiques," 

 which precede the plates at the end of the volume. 



In Chapter VII. Desmarest gives notice that in his o\vn classification of the Crustacea he pro- 

 poses to follow essentially that inserted by Leach in the eleventh volume of the Linniean 

 Transactions, but modified and expanded to adapt it to the improved state of science on 

 the subject. He had already explained in the preface that he had improved Leach's system 

 by grafting upon it that of LatreiUe. Accordingly, he makes two subclasses, the Malacos- 

 traca and the Entomostraca, each divided into five orders. The Malacostraca are divided 

 into two legions, of which the first, the Podophthalma, includes two orders, the Decapoda 

 and Stomapoda ; the second, the Edriophthalma, contains three orders, the Amphipoda, 

 Lasmodipoda, and Isopoda. As usual at this period, the mandibular palp comes into the 

 definition of the Amphipoda, and is denied to the Loemodipoda. The Amphipoda are said 

 to have five pairs of false feet under the tail. 



The distribution of the Amphipoda is as foUows : — 



" I" Section. Deux antennes inserees una de eliaque cote du front ; queue ierminee par des filets 

 styliformes ; tete grosse, verticale." 



This includes Phronima, with the species sedentaria and cusfos. 



" 11" Section. Quatre antennes ; deux feuillets aplatis, gervani de nageoires, places au bout de la 

 queue, et rempla^ant les styles; tete grosse, verticale." Herein he places Hyperia, Latr. 

 " Quatre antennes setac^es. Les dix pieds, proprement dits, mediocrement longs, et tons 

 terminus par un article simple et pointu. Tete assez petite, roude, plane en devant, point 

 prolongee en rostre. Corps conique, termine par deux lames triangulaires, alongees, 

 horizontales. Hyperie de Lesueur ; Hyperia Suerii, Latr.; Phronima? ejusd., Encycl. 

 Met. Crust., tab. 328, fig. 17 et 18. Nota. Je dois la communication des caractferes de ce 

 genre inedit a la complaisance de ]\I. LatreiUe, son fondateur." In this section he also 

 places " Phrosine {Phrosine, Risso ; Dactylocerus, Latr.)," with the species Phrosine 

 semilunata and Phrosine macrophthalma. 



" IIP Section. Quatre antennes ; queue terminee par des filets styliformes ; tete mediocrement 

 grosse, nan verticale. 



" I™ Division. Antennes formees de quatre articles dont le dernier est suhdivise en plusicurs autres 

 fort petits ; les superieures tres-petites et plus courtes que le pedoncule des inferieures, qui est 

 compose de trois articles." Talitrus with the species locusta, and Orchestia with the species 

 littorea occupy this division. 



" 11° Division. Antennes grandes, setucees, formees de quatre articles dont le dernier est lui-meme 

 muUiarticule ; les superieures de Ken peu plus courtes que les inferieures." This division has 

 only Atylus, Leach, with the species carinatus of Fabricius. But the remark is added, 

 " M. LatreiUe presume que le Gammarus nugax de Fabricius, figure par Phipps (Voyage 

 au pole bor(5al, pi. 12, fig. 2), appartient au genre Atyle." 



" HI" Division. Antennes formees de trois articles dont le dernier est midtiarticule, et dont le 

 premier est le plus pietit de tous ; les superieures etant les plus longues." The genus Dexamine 

 is included, with the species spinosa, and this is followed by " Leucothoe (Zeucothoe, Leach ; 

 Gammarus, Latr.; Cancer, Montagu ; Cuvieria, Leach)," with the species articulosa, but no 

 explanation is given to show where the synonym Cuvieria for the genus is to be met witli. 



" IV" Division. Antennes fonnees de quatre articles, dont le dernier est muUiarticule ; les 

 sujyerieures etant les plus longues. 



"Subdivision I. Les quatre premiers p>ieds monodactyles ; ceux de la seconde paire dans les males, 

 ayant la main dilatee et comprimee." In this subdivision is included " MiiLiTE {Melita, 

 Leach; Gammarus, Latr., Lamck.; Cancer, Montagu; Boscia, Leach)," with the species 

 palmata, and "Maeka (Mxra Leach; Gammarus, Latr., Lamck.; Mulleria, Leach), with 



