on the shore. /^mtr''S-'^' "' ^'CCm 

 asck-s, as ivell as W/'jJ'rJr} W,'#//"' 



at they tut tlie --^ 



428 CRUSTACEA. 



Podocerus, Leach, and lassa, Leach, have the inferior antenna; greatly elong'ated in the form, and occasiunally 

 assuming; the functions of letrs and or2;ansaf prehension ; their second legs are terminated by a lar:^-e claw. 



Coroji/iiin/i, Latr., Iins similar lower antenn-x, but none of the le^s are clui-liferous. The type is Cancer 

 grossipcs, 1 jjin,, I :iiiiii/iiin>:; lnn'j'nonin, Fab., Onhviu volutatur, Pal., and which is named Percys on the coast of 

 La Rochclle, liviuy* in biu'rows, which it forms in the sand, covered by hurdles, called buuchots l>y tlic in- 

 habitants. The animal only makes its appearance at the beg^innino; of May. It keeps up a conlijiual war 

 with the Nereids, Amphinoma?, Arcnicohe, and other marine anuelida: which take up their abodt.^ in the 

 same place. NoHiiir;- is nmri- rurinus ilwiii tn oIisit\(-' tlic-c cn.'aiui-es at the rising of the tide assuiubltd m 

 myriads, mn\ in-; ahmit in all diri.'clions, lir;itiii[;- Uk; mud \-> iili llirir arm-ljke antenna:, and diluting it in order to 

 discover their prey. If they discover any of these annelid;c, often 

 ten or even twenty times larger than themselves, they unite 

 together to attack and devour it. The carnage never ceases 



until the mud has been turned over and examined. They ,<f~rCtVVl^?^ 



also attack fishes. molUisca, and dead bodies 

 Thi.-y mount upon the hurdles which contain muscles 

 upon the latter, and the fishermen pretend that they 

 threads which retain the muscles, in order to cause the latter to Fig-, 12.— CoTophium ioiii;icr,rne ; a, temihiai scfmcnt <nf 

 fall, so that they may be the more readily devoured. They appear ^ "" '" ' 



to breed throughout the season, as the fenjaies are found carrying eggs at dilTerent times ; shore-birds and Uiany 

 kinds of fishes devour them. 



Tlie second of the sections of the order Amphipoda, or tlie IIeteropa, Lat., is composed of those -uhich 

 have fourteen legs, tlie four posterior at least being unarmed at the tip, and tit only for shimming,'*' 

 and forms two SMli;^^cnera. 



_P/tV7/_(/y«;'/r, Latr., has the thorax di\ided into numerous sei^ments, four aritenna% with long hairs; all the 

 legs natatorial, and of wdiich the posterior are large and jjennated. [Type, Oniscus arenarius, Slabber.] 



Apsc'udes, Leach {Eiqjhciis, Kisso), has the thorax divided into numerous segments, the fore pair of legs 

 terminated by a large claw, the second pair of legs with the terminal joints very broad and toothed [whence the 

 specific name of the type, A. ialpa, Leach, Montague, from its analogy with the Mole] ; the other legs are single, 

 the body is long and narrow, terminated by two long threads. 



Rhma, Edwards, ditlers from the preceding in having the superior antenn;e tliicker, longer, and bifid. 



The third and last section of the order Amphipoda, or the Dkcemtoda, Lat., consist;, of species 

 having only ten feet. 



T?/^///^, Risso, has only two aniennae; the head is large, with prominent eyes; each pair of legs is attached to 

 a distinct segment ; the four anterior arc terminated by a didactyle claw. On each side of the thorax, are two 

 moveable plates, forming two valves, beneath which, when at rest, the animal shuts its logs and tail, giving it the 

 appeai'ance of a ball. Type, Ti/phis ovoides, Risso. 



Ancviis, Risso, Gnnihia, Leach, has the thorax divided into the same mmiber of segments as there are pairs of 

 \o'X-^, \\hicli are simple and monodactyle. They have four antennae ; the head is large and square, and furnished 

 in fi'ont with two great projections, like mandibles. Type, Cancer ma.rlUaris, Montague, Trans. Linn, ^^oc, 

 vol. vii. pi. 6, f. 2, — found on the Devonshire coast. 



Pr«»ira, Leach, has four antennce like the last, but the tlmrax from above iirescnts only three sigmcnt:^, of 

 which the two anterior are very short, and the third very large and oval, having the three posterior pairs of legs 

 attached to it. The legs simple, the head triangular, and the tail furnished at the sides of the extremity with a 

 swiinniiTrt. [1 li;t\c iiivestiL^atcd thi; structure of this curious genus very miiuitrh', and |lubli:^hed the re.suit 

 thereuf iti the Aiuia/r.s <'a.- ,S,:n-Hre.s N,i/'!rr//c^\ vul. x.wii.] 



To this order abo appear to belong various other genera, estuhliihcd by Savigny, Ratiuesque, arnl 

 Say, hut of which the eliarartcrs liave not been hitherto given with suilicieut decision ; and evcii of 

 those eilcii aluAc :^nnn^ r(.'quire a rc-cxamination. 



i\I. Mdue Edwards has collected many valuable and detailed ol)servations on many of these Crustacea, 

 which will serve to clear rip much of this obseinity. I am not able to speak "with precision also of the 

 genus Erf/iaa of Risso. From tlie number of legs it appears to belong to the last section of the Amphi- 

 poda, but the manner in wliu;h they terminate, and the number of the segments of the body, range tlieni 

 amongst the Isopods. 



[Since the publication of the secoiul edition nf this work, the Amphipoda have received a consider- 

 able share of atvcniiiui. M. Milne Edwards, in the Annales dea Sciences Naturelles for 1830, published 

 a revision of the order, di\itiiug it into two principal groups, (removing the genera Rlnea and Tanais to 



