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



Sectio II. lias the following arrangement: " Divisio L Antennx 4-articulatse, articulo ultimo 

 e plurimis segmentis minutis efformato ; superiores brevissimae, inferiorum pedunoulo brevi 

 ores." Gen. 2. Talitrds, Lafr., Bosc. Pedes quatuor antici in utroque sexu subfequales, 

 monodactyli. Antennx superiores articulis duobus inferiorum basilaribus breviores. 

 "Spec. 1. Talitrus locusta." "Gen. 3. Orchestia," Leacli's own genus re-defined: — 

 "Pedum paria quatuor antioa maris monodactyla, pari secundo manu compressa magna; 

 rcEMiN^ pari antico monodactylo, secundo didactylo. Antennx superiores articulis duobus 

 basilaribus inferiorum hand longiores. Spec. 1. Orchestia Uttorea." 



"Divisio II. ^wfe?iwaquadriarticiilat», articulo ultimo e segmentis plurimis aUis distinctis 

 efformato ; superioribus subbrevioribus. Gen. 4. Atylus," with the observation, " Generi 

 Dexamini valde affine est hoc genus," and " Spec. 1. Atyhis carlnatus" Fabr. 



" Divisio III. Antennx triarticulatfe, articulo ultimo e plurimis aliis distinctis confecto, superioribus 

 longioribus. Gen. 5. Dexamine." Spec. 1. Dexamine spinosa; "Gen. 6. Leucothoe." 

 Spec. 1. Leucothue artieulosa. 



" Divisio IV. Antennx 4-articulat8e, articulo ultimo e plurimis articulis efformato ; superiores 

 longiores. Subdivisio I. Pedum pur secundum maris manu dilatatd compressa. Gen. 7. 

 Melita." Spec. 1. Melita 2>fdmata ; "Gen. 8. Maera." Spec. 1. Maera grossimana. 

 " Subdivisio 2. Pedum paria duo antica in utroque sexu monodactyla conformia. Gen. 9. 

 Gammarus, Antennx superiores ad basin articuli quarti setd parvula articulata instructae. 

 Cauda superne fasciculato-spinosa. * Cauda stylis gemlnatis siqKriorihus stylo supero hrevis- 

 simo. Spec. 1. Gammarus aquaticus. G. processu inter antennas obtuso rotundato," with the 

 synonym "Gammarus Pulex. Leach, Edin. Encycl. vii. 402-432." "Spec. 2. Gam- 

 marus marinus. G. processu inter antennas subacnminato." " ** Cauda stylis geynimxtis 

 superioi'ibus stylis subxqualihus. Spec. 3. Gammarus Locusta." Spec. 4. Gammarus 

 Campylops;" "Gen. 10. Ampithoe." Spec. 1. Ampithoe ruhricata ; "Gen. 11. Pherusa." 

 Antennx superiores seta nulla ad articuli quarti basin. Cauda superne baud fasciculato- 

 spinosa. Manus filiformes," a definition which differs from that of Ampithoe only in the 

 substitution of filiformes for ovatiB. The type-species, Pherusa fucicola, is stiU only de- 

 scribed by its colour, which, according to Leach's own rendering of his Latin, is " testaceous- 

 cinereous, or gray-ciuereous, mottled with reddish." 



" Divisio V. Antennx 4-articulatse, inferiores longiores, pediformes. (Pedes quatuor antici 

 monodactyli.) Subdivisio 1. Pedum par secundum maim magiia. Gen. 12. Podoceeus." 

 Spec. 1. PodocefTUS variegatus ; " Gen. 13. Jassa." Spec. 1. /a«sa ^Zc/«eZta. Var. a. manu 

 eecunda dente elongato, obtuso ad interni lateris basin. Var. /8. manu secunda latere interno 

 tridentata ; Spec. 2. Jassa pelagica, and the observation, " Gammarus falcatus, Montagu, 

 Trans. Linn. Soc. ix. ad hoc genus pertinere videtur." Subdivisio 2. Pedum par secundum 

 manu haud magna. Gen 14. Corophium. Latr., Spec. 1. Corophium longicorne. 



" Sectio III. Corpus depressum. A. Cauda inermis. Divisio I. Corpus 6-articulatum, seg- 

 mentis omnibus cum capitis basi pedigeris. Pedes 14 ; paria duo antica ungue mobili, 

 (pollice) instructa ; par anticum minus, ad caput annexum, carpo articulato ; paria tertium 

 et quartum ssepius spuria ; piaria sex posteriora coxis aliquot productis, unguihus validis 

 armata. Antennx quatuor, superiores longiores. Os palpis duobus apice ungulatis. Anus 

 tuberculis parvis obscuris. Bursa {uterus externus) valvuUs imbricata inter fceminse pedum 

 paria tertium et quartum sita est, qua ova, pullique post exclusionem educantur. Animalia 

 parasitica in Oceano degentia, Fucis, Cetaceis (Piscibusque "i) arete affigentia. Subdivisio 1. 

 Corpus lineare. Oeuli pone antennas superiores siti. Antennx i-ariiculatx, superiores 

 segmento ultimo aliorum longitudine, e plurimis aliis compositis ; inferiores subcompressx, 

 superioribus dimidio nmiores. Pedum par anticum {Palpi Montagu) os prnpe situm : 

 secundum manu sxpius intus dentatd." Gen. 15. Proto. Pedum paria secundum, tertium 

 et quartum basi appendiculata. Pedes omnes valide unguiculati. Ad hoc genus pertinet 



