96 THE VOYAGE OF H.M.S. CHALLENGEE. 



pour en former un ordre special. Ses caracteres out ete developpes h I'article Ctstibhanches. 

 V. ce mot." Already to the article on the Isopods, his fourth order, he had appended a 

 note, " On pourroit former un ordre ijarticulier, sous le nom de lamioclipodes ilxmodipoda), 

 des isopodes cystihranclies. Leurs quatre machoires sont disposees sur le meme plan 

 transversal, en forme de Ifevre, comme celles des myriapodes; la premiere paire de pieds 

 proprement dits est annexee h. la tete ; ils n'ont point de branchies sous la queue; de petits 

 corps vesiculeux, analogues h. ceux qu'on voit k la base des pieds des araphipodes, paroissent 

 en tenir lieu." 



These Lxmodijjodes, he thinks, lead towards the Myriajjods or the Pycnogonides. 



Tliroughout the work the various genera of Amphipoda and Liemodipoda accepted at this period 

 are discussed in the alphabetical order of their French names, but without, so far as I have 

 seen, any novel information being contributed. In most instances the French and Latin 

 names begin with the same letter, but Gammarus is an exception, being in French Crevette 

 or Chevrette. Of the " Crevettines, Gammarinx," Latreille says, " J'ai, dans mes ouvrages 

 pr&edens sur I'entomologie, d&ign^ sous ce nom une famille de crustac^s composee de 

 ceux qui forment aujourd'hui I'ordre des avijMpodes et la division des isopodes, que j'appelle 

 Gystibranches." 



1816. Risso, A., born 1777, died 1845 (Hagen). 



Histoire naturelle des Crustaces des environs de Nice. Par A. Risso. Ornee de 

 gravures. A Paris, 1816. 



Eisso begins with a quotation from Cuvier, " La determination precise des especes, et de leurs 

 caracteres distinctifs fait la premiere base sur laquelle toutes les recherches de I'Histoire 

 Naturelle doivent otre fondi^es," &c. Eisso's own intention, doubtless, was to act in 

 accordance with this maxim. Nevertheless, the species he established have in several 

 cases caused great perplexity, owing in part, perhaps, to the want of repeated researches in 

 those localities in wliich Eisso's specimens were taken. In discussing the habitations of 

 Crustacea, he regards Talitrus as amphibious, delighting in the rocks ; Caprella (les 

 chevrolles) hides under stones covered with fucus ; Cyamus attaches itself to cartilaginous 

 fishes ; Phronima floats on the surface, leaps lightly out, or penetrates to small depths 

 below. Typhis is found beyond the Zostera zone. 



He divides the class Crustaci^s into two orders, the first " Cryptobranches. Tegumens duis ; 

 branchies cachees sous le corcelet; yeux pedicules; sans palpes ou antennules ; dix pattes 

 foliacees ou mutiques," subdivided into two sections (1) Brachiures, with two families 

 containing between them eleven genera, and (2) Macroures, with three families containing 

 among them seventeen genera ; the second, " Gymnobranches. Tegumens coriaces ; 

 branchies cachees ou inconnues ; yeux le plus souvent sessiles ; mandibules palpigeres ; 

 dix pattes ou plus; termin(5es par des crochets," subdivided into three sections (1) 

 " Squillines. Tete distinct du corcelet ; " (2) Tetraceres ; (3) Entomostrac(.'s. The SquilUnes 

 include two families, "SquiUares. Queue munie de lames ou de filets, yeux pedicides," 

 with the genera Squille and Mysis ; " Crevettines. Queue aveo ou sans appendices foliaces, 

 yeux sessiles," with the genera, "31. Phronime. 32. Typhis. 33. Euphee. 34. Talitre. 

 35. Crevette. 36. Chevrolle. 37. Cyame." The second section, T^tracferes, contains 

 two families, Asellotes and Cloportides, each with six genera ; the third section, Entomo- 

 straces, contains two families, the Clyp^aces with one genus, and the Ostracodes with two 

 genera. 



The Isopod Anceus, it may be noticed, is here given as a new genus, among the third family, 

 Paguriens, the first of the Macroures. It is, in fact, a synonym of the genus Gnathia, 



