4V2 



CRUSTACEA. 



Britisli species, having; the frontal rostrum not extending beyond the peduncle of the superior antenn;p, and 

 nearly straight. 



[(.)ther g-enera have been proposed by Risso. Leach, P. Iloux, and 'M. Edwards, founded upon \ ariations in the 

 form and propoftions of the le,i;s.] 



PcM^^Atf^, ^avigiiy, is a very interesting genus, allied to tlie preceding iii the upper antennfe, terminated by 

 two filaments ; the four fore-legs terminated by a didactyle claw, but [difTering fiom all tlie other Carides] in 

 having the external base of the legs furnislred with a thread-like appendage; the claw-legs are larger, nearly equal 

 in size, very slender, and filiform ; the body is very long, very compressed, and very soft. I'ype, P. iiicado, Kjsso. 

 Found in the Mediterranean, especially in the Bay of Nice, where it is very abundant.* 



The fifth and last section of tlie ^facroura — tliat of the Schizopoda — appears to unite theiu with 

 the suhsequent order. The leers are very blonder, like flattened threads, and not furnished "witii claws, 

 but ba\ing a longer or shorter lateral appendage arising on their ontside near the base, and [the legs 

 are] fitted oidy for swimming. The eggs are borne between them, and not under the tail. The ocular 

 peduncles are very short. As in the majority of tlie JIacroura, the front is prolonged iido a kind of 

 rostrum. The carapax is very slender. Tlie tail terminated, as is cust.on;iary, in a swimmcrct. These 

 Crustacea are minute and marine. 



In some, the eyes are very apparent; the lateral antennae furnished with a scale; the intermediate 

 ones terminated by two filaments, and composed of many minute joints, as in the preceding. f 



3/^i7s, Latr., has tlie antenute and legs uncovered; the carapax long, nearly square, or cylindrical ; the eyes 

 close together; and the legs capillary, and formed of two thread-Ihce iha- 

 ments. Type, M. Fabricii, Leach ; Cancer scutatu-s, O. l-'abricins. 



[Tlie species of Mysis are termed Opossum Shrimps, from their singular 

 economy of carrying their eggs and young in a large pouch, with njem bran o us 

 envelopes, beneath the thorax and between the thoracic legs. Their structure 

 has been fully investigated by Thomp.son in his Zoological Researchea;. In 

 the Encyclopcdie Mtihodique are also some figures communicated by Dr. 

 Leach to Latreille, and evidently intended for the Malacoslraca BrUuiinua 

 of the former author, but which were never published by him. 



Two other genera, nearly allied to Mi/sls, have been proposed by ThonipiOiij 

 founded upon oceanic species, namely : — 

 ■ ibe C II 111 Ilia, having bra nchice attached to the subabdoniinal fins ; and NoclihiL-a, 



founded upon a luminous species^ but not described with yulhcient precision, 

 and omitted by M. Edwards, 

 which there are also eight pairs of bifid natatoiT feet, but the branchiae are in the 

 branous appendages, at the base of the true legs. 



».v, Tilesius (in the Neue Annahn Wetteramch Ge.u-ll'ichnff, vol. i.), coir,idered by 



and ih-AXoi Podop- 



T/n/,s'aiiOpoda (Ed'.\ uv^ 

 form of many-branrbril 



The genera P/(f7,s»/"/..'"//T/»"-v, Tilesius (in the Neue Annalcn Wetteraii^ch Ge-wll'irhaft,\ 

 Thompson and Edwards as undescribed, and named by the former Lucifer {Leucifer, Edwards 

 ms by Thompson, are amongst the most singular of known Crustacea, having a liliform body, with very large 

 globular eyes placed at the extremity of very long and laterally extended foot-stalKs ; and the legs are exceedingly 

 slender and short. According to Slabber, whose figure of one of the species has been overlooked by all Crustace- 

 ologists, there are eight pairs of legs of equal size.] 



Cryptopm, Latr., has the carapax subovoid, swollen, bent under at the sides, enveiopmii- the body, a.s well 

 as the antennae and legs, having only on the under side a longitudinal slit. The eyes arc wide apart. Thu 

 legs are like flattened threads, with a lateral appendage. Type, C. DefrancU, Latr. iMeditcinimMU. 



In others, the eyes are hidden. Tlie intermediate antennje conical, exarticulated, and very short. The lateral 

 antenuEE composed of a peduncle and a liUuncnt, without distinct articulations : thtir ba^e is not protecttd by a 

 porrected scale. 



Mulcio, Latr., has the body very soft; tliorav ovoid; legs like flattened threads, the majority witb an ap- 



* [Many ridiJifinnnl ffiriiera hnve beer) fiddc.J to the Ciiriili.s bv Pol 

 dore RuUY HI Ills Mein^ne ailr /./ Cl':.<f{h''>lnn, (/-■,■; ('ru::/u>.:^ df 

 Tribu dei Sa!lr'jrj,ic.t, Miirstillrs, I^IU ; nriil hv Mili.r Kdiw.r.i.'; i,. il 

 AniK'lea d^a Sciei.res NufarfUr^, iiiul //i.i/. Nnt. des Lru.Hi,i:i's. I 

 these it will be neu-cssHry onlr lo iknic- llniHe of 6'c^oni«, uenr 

 allied to PeiiiBus, bat d[lT..riri^,r jrinu it and all tlie other gcner;i 

 having; iiu appeiidngeH tu thi lalse .subiiljdoininul Icki, ami in ihi; mnt 

 IJcaUons of its re.spiratory iqiparatus, there bcinti only vU'. rn |i.iir-. 

 branchias instead of eig-liteen. Sergtu'/s and ^■Jclr^—in «iii. Ii il 

 posterior pair of true le^rs i.s almont rudimciital, or entirely o(i.m>Ul 

 tlie outer pair o( foot Jiiwa beir,g immensely developed, so as to coiihI 

 tute an aiiierior pair of le^s to supply their place. These yenera a 

 lOiin-led i,|.no ,-,,r.ic ^p-'nrv] 



[Her-' li.TniNi tl. -,, 1,1 rlir .-.ysfe.Li 0[ M Kil»','irfl :^, the (J'-eal Order 

 Decapo-I r,-u^i..c'.i. uli.el,, u, In.s /Ir.t. .\.,(. drs CrnstuU'^, i.i ,su 

 ceeded by :<n nppei.dix eoii-,i.stiii|,' o( ■' iJeeiipodei doutcuii." eninpri 

 ing- the genera Zoeh, Ceratiispis, Mulcio, and i'osydoii. WUli rci-pt- 

 to Zoea, I liave clearly proved in my Ulcnioir, publislied in tlie P/iii 



soph'iral Trnum'-iioTtf, that it is ,i i)i.e.i|)od ; w\ tlierefure the observ.i 

 lions ol Latreille, .it tliO end ol tlic L>tc;ipods, L-jniiot be a.UqileO.J 



t [The Schizopoda luiviii;;, sir.ce Lhe piibiiei.lioii nl tlie second edi- 

 tion of thhs work, been «ell invesiigaiid by Edwurds and ThoQ.pjoD, 

 have been found to be more nearly allied tu the order Stoai»poda. 

 although preseiitint^ so ncn-r a rtsembliince to the Oiirides, This iiii^o- 



vnt was adopH^d by Latreille hiiiihelf in hxa Cunr-i d- E>:l>,n<ulni;u' . 



Ill M liieh this author has proposed to give tliL'-e l'i>d,.|ii!-i,il junu, 

 I niM.i. L-a which are debtitute of ihoiaeic intL-ihil hi-,u.>. I,i..^, bul 

 oLlu-rwise resembling the Carides, the .seclioiml name ol CuLUvide-., 



moiiv;.. ,,rgan^ ; and as each ot these is divined Ir.Mi, Un: base liy U,c 

 ;iddiLloii of a lalera] appciidaise, these animals may be said lo hawj not 

 lewerthan lldrty-tno letTs.J 



