Bull. Kanagawa Pref. Mus. No. 6, «1973

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1 JHuwwffc, rm Bull. Kanagawa Pref. Mus. No. 6, «973 ft ffl» tt On the Characters of the Larva and the Seasonal Change of Occurrence of the Sargassum Crab, Planes cyaneus DANA Kensaku MURAOKA SYNOPSIS The Sargassum crab, Planes cyaneus DANA is usually found among the Sargassum weed and on the floating timbers, and is distributed from Tokyo Bay to Kyushu and Okinawa in Japan. The megalopae were obtained from Sagami Bay and have been reared in the aquarium until developing into the first crab-stage. They were morphologically studied comparing with those of the other related species. The young and adult crabs were collected during September, 964 to December, 965 to examine the seasonal change of occurrence of the species, and occurred abundantly in summer, but not in winter. The author could find the size of ovigerous crabs which was 3 to 20»», approximately. The females seem to carry the eggs from middle of May to early in July. The features of megalopa are summarized in the following, and also the size of male and female crabs and ovigerous period are shown in Fig. 4. Description of Megalopa-Stage The carapace has no dorsal spine or protuberance, and dorsal surface is smooth. The posterior portion of the carapace is not marked with grooves. The size is approximately nn in length and.5»» in width. The proximal portion of antennul is composed of three segments. The endopodite is composed of two segments. The exopodite is divided into four segments. Each of the second to fourth segments is furnished with numerous longer aesthetascs. The antenna has a single flagellum which is divided into eleven segments. The mandible has a palp, which is composed of two segments, the distal one of which bears 0 setae and a few plumose hairs on the lateral margin. In the

2 maxillule, the endopodite is slender and bears long seta near the proximal portion. In the maxilla, the endopodite bears 7 plumose hairs along the lateral portion. The first maxilliped consists of a unsegmented endopodite, bearing 6 short setae on the distal margin, and three-segmented exopodite, bearing 3 plumose hairs on the distal margin of the proximal segment and 6 apical plumose hairs on the terminal segment. The second maxilliped is composed of two parts, the endopodite and exopodite. The endopodite bears many strong setae on the distal portion of terminal segments. The exopodite is divided into three segments, the distal one of which is furnished with about 5 apical plumose hairs. The third maxilliped is well-developed. Its endopodite bears numerous stout setae on the lateral margin. The exopodite is divided into three segments, the distal one of which bears about 4 plumose hairs. Cheliped has well-marked segment, and the palm is swollen. In the ambulatory legs, the second and third pairs are nearly equal in size. The last pair is reduced, and the dactylus is furnished with the fine setae and the tip of fingers with three long hairs. The abdomen is divided into seven distinct segments. The pleopods are furnished with 4-6 small hooked hairs on the endopodite, and with 26 to 38 plumose hairs along the lateral margin of exopodite. The uropods are furnished with 3 plumose hairs on the proximal segment, and 20 to 23 same ones on the distal segment. It D #> l~ i Vii~m V fi -mm^-wk-f % * * i- fi^ $ -Planes cyaneus D A NAlifl*8M tf>;*/ Planes &<D*jj n '<tf> ) *?. * * t i] V % -\z~0\ ^(D^WM<^%l^\t^htz b & W LfrL JZiBftM<DPlanes minutus ( LINNAEUS) CO^^CD^^BjfcOOTIi HYMAN (924), LEBOUR (944) ^ i ^ ^ S o ^CDlh HYMAN (i» b Mlt Z&tz /* 7\Z OUT, Zfz LEBOUR l±9$frhfflit2-&fz, /*7, i ^ ^ i i L T j f c / ^ o ^ i, Zttilz, C<DS tf v^cd^&m^^^m^zte^te^fzo Ti2, C(D^^.(D ft$ffi&m&% i k~?z t t blz, '&%m&-$tfx\^z Planes m<nth.\z-o\^ti}kifc&-te dfcofco 2 hlz~z<n* -<n\iim$%l J $ > fe9$<nmfflz''d\^x i, &i tf>-)x> *>«(# > mzm^^zfttlh, mi&znm*^*>^tz^wlm &m#un±\z&<mmz%-r %o ttzun^n^\z-htz^x^±^c^m^\^tztz\^zmmn^^mm^m^mm^i

3 47 m%ilzjijl ^c^-^ ih, * ii P ^Ii 3 {lal^t, C:ff>9 "^ff> {^*972^ 3 M30BIf a]mthr}t^«^w^a(cr;mltl Vctfit^ b, fi!i<7> 2 f[*l#: il972^ 4 )\ 2 B #^Ji M {(]i(c/#p^<^ <7>fc, nl&m^frbnbtitzwbit, b(cl972^7j!26b, $L >m'w.w:?s:m^ntz, *%*'-&%mmlfzm i w^m^rz^cm ^- 0 T\*z<nm : M%iffl'pnbtLti:frvrz<n-?, W2^3MTmim^nfzttnzmx^0 /tfp^au : E F;xli^ 3.5~4.5>M, I I@ »*T, ^MMML, tra'b^t, tt^ & lig #> *>*i&v ^ &Mm\z~%Kfrzm4^P^iJx^l-^/i^^^limWTIi^ ^ (Fig. l.) 0 miftkftl±mtt3wo rtj&li2 0T, ^0M(cii2*<^M^H #>b*i3o «li4 &%k ^6^^4-itP^ (Fig. 2.)o <7>^(Cli2S^ lm^ktfbftbtiz (Fig. 2, B) D Fig. l. Megalopa of Planes cyaneus DANA, dorsal view.

4 48 k$l*<dm$i%&mtf)h*i5 (Fig. 2, C)o mtbbti* (Fig. 2, D) 0 Fig. 2. A; antennul, B; antenna, C; mandible, D; maxillule, E; maxilla, F; first maxilliped, G ; second maxilliped, H; third maxilliped, I; uropod. The bar scales represent mm.

$49 3 (Fig. 2, E) 0 mimummw, SIP, i^&wkici^ftso imtm$\z\$\mmzmm\^ 6 ^ ^ ^ n? a ^ 4 ^ t l ^ (Fig. 2, F)o m2i!$

5 49 3 (Fig. 2, E) 0 mimummw, SIP, i^&wkici^ftso imtm$\z\$\mmzmm\^ 6 ^ ^ ^ n? a ^ 4 ^ t l ^ (Fig. 2, F)o m2i!wirt^klz^^n, rt&li4tefistf>*b*iso *U li3teflgtf>fe*is#, H20 i^lpi^ipli g#tli^o 0 *l flcli5*<75^^ ^IS^^*i-5 (Fig. 2, G)o g3mpiirt«nc^ft, rtklisgfrfg^bftso «li30t^kj:>9^<, H 2%vtm%t<Dm$'%2mmmmw-vw \" (Fig. 2, HX «ii; ^L<, MSP, mwthffihfr-v&z (Fig. 3, c)o ti% 0 mi^m^%^m^\t3^f(dm%^i^^^x.x\^ (Fig. 3, DX ngpii 6 mpi JIIP^*b & So n 2EK^ b^ 5 mmmtmzii n<d=ixirzm& tp5o ^6IIgplilx^JlK^^^x., *<^Ifflcii3#<7*E#, *I(Jlcli20~23 ^l^^id^wj:x.tp«(fig. 2, I) 0 Fig. 3. A; anterior region of carapace, dorsal view, B; same, frontal view, C; cheliped, D; fourth ambulatory leg, E; abdomen, dorsal view. The bar scales represent mm.

6 50 FEMALE MALE CO _l < D O O cc 00 0 L LL young crabs CARAPACE WIDTH u..ul II,,_i J. 0 with ova (mm.) Fig. 4. Relation between the carapace width and the number of crabs. 2. **-r-ft \^ii-<nw i%(n^%mwit

7 5 ^SiJjdl^iCi >(>!<»{ (;: oi ^T(iFig.4 \z-ffltzo l i i tl^# <f?^^i/z^li 5 /J tbbtitzo t &znnb*itzmfo\i^lb>\^fr^tztf, zwtmwm^'&tzwn:^ <$*»>;*: Tli, lllt S^i ii<^jl- 22^T, CftJ: 9^ 4M@f (±f#b*l M<D-XZ tw\lxh^ tzo L^ L d CITIi 6.3«i^T^A ~<7>flf H(;:oi ^Tli^ds^iJ f^ilil-fc^o/itf*, WifcJ:oT(i,f]gK^^S^b^lfflg^T', «^I,(;:i$ sy-tscii^tts mm, i963) Q bntz\ Vf~z foz> 0 mitl± 6 n l^nbtlfz^mxhhkd t <D~?h o tzo fc t" Xf ±^m^,&i- %**i-jivfi=-\t kmxmm^&i- %nt n nx-r^x pianes minutus t ZtlX\ "fz 0 MteX\±M<nMffi** B% <F>fcBfrb± ft <nm\± Planes cyaneus tztlxx^z ( CHACE, 95)O ifc^35il:4,lt5l4p. c^»««sf, CO WcO&M.btlZ ( SAKAI, 965)O Planesj$ ] <DW <7)^^(D -) h, LEBOUR (944) li P. minutus CO / # n ^<75^BPM! (COOT, ^E^^!#itWJfflPt gsltp5o :CTIi LEBOUR " «fc ot g^ ^WL<nm±\l\S &l-to-5#\ ^t$l:optiip. minutuscoll 7 tf^^'kfcx'fo -So ^4^JSP^IP^ooT!i*^d i btl^iif:^^i((i-&-t'5o If^^Mffl^IS^bti-So L^LMK^*0iJ (Table ) 0 rtib<7>#»bm?l<7>^ # n '< «SS!J $ bi^ <Dm&xmm$$frbntz 5 ~ 6M^KIM^OI ^limw^ji-xim^^ i(5!i' s]lit^^^i^b, ctib^fisiio-ftii^lfim^, ^-5o(i^ti(ci ox

8 52 Table l. Features of the megalopa of Planes cyaneus and related species. carapace length feders j uropods ; (mm) j proximal seg. terminal seg. Planes cyaneus P. minutus frhsn^frh^k 7 nfrh8mlzwx&&<, 9Mfrhl2MlzWXl±, 0fl Kn^ Tii^li^^PiP^ (.«;, 963),. tfzz.<n~mff\lzm'ml, riwm?z**i-xi>'rt -i:optii, fom Q964) <Dm&lz titf4mtujfrb6 8±h]lzfrix<nM\ti\RV8 tilz&ml, tf>-5*>5j!fi$&#<, 32f H#: f*ffilto3 0 Z<nm r?fti]k<r>m& feip^jcootfi, ^<nm^xmmwfimbtitz<n\tbnfrbin\^\ixx, m frf *xna%. mi-zzk^f Z 0 rz*u<n*tf * 'Mi 3 J!(eff btifztf, <&-?Lb Z.<r>WzW*-x n ^^tijmtfi l^ (LEBOUR, 944) 0 L #? otffl: fc P t 4, ^<7)^ ffc * # n ^^fcrj^-f-5 CI Aikawa, H Further notes on brachyuran larvae. Rec. Oceanogr. Works Japan, 9: Chace, F. A. Jr. 95- The oceanic crabs of the genera Planes and Pachygrapsus. Proc. U. S. Nat. Mus. 0 : Edmondson, C. H Hawaiian Grapsidae.5. P. Bishop Mus., Occ. Pap., 22 : Gurney, R The larvae decapod Crustacea. Ray. Soc. London, mnmx, H= jm 967. ^yr-ix-m^mi, ^&mm, ^m^xumm. A±^tsmm, 23 (2).'8-89. fcm^fr mtmt-o< MM<n*kim : &imft, i. it^aam. ^mmm, 6: ffitmt-d < ^m^^m^mm,. MM^O»» wsm 62: Hyman, O. W Studies on larvae crabs of the family Grapsidae. Proc. U. S. Nat. Mus., 65 : -8.

9 OTHJTPft 963. X7 4 # = <7)00<7)BI ICO^-C< > =< >#. 07.RM&, : B«IC&lt<5X7^ ^-O^SICMI-'SW^. I- ^ifsmkio-'epmso TOgfL^$*ffl2*l*$M*- / fi. B*Wfl?fr, 22:8-6. Knudsen, J. W Observations of the reproductive cycles and ecology of the common Brachyura and crablike Anomura of Puget Sound, Washington. Pac. Sci. 8 : Lebour, M. V Larval crabs from Bermuda. Zoologica, 29 (3) : fcrflbh&ft" i, 3 7 */ vii = Plagusia dentipes DE HAAN<7) J$i# <7)^-&' 4$ICOV ^. ^mmmm, : Muraoka, K. 97. On the post larval stage of the three species of the shore crab, Grapsidae. Bull. Kanagawa Mus., (4) : Rathbun, M. J The brachyuran crabs collected by the U. S. Fisheries Steamer Albatross in 9, chiefly on the west coast of Mexico. Bull. Atner. Mus. Nat. Hist., 48 : Sakai, T The crabs of Sagami Bay. Tokyo

H. MILNE EDWARDS (Crustacea, Brachyura) Reared in the Laboratory

Larval Development of Sesarma (Holometopus) dehaani H. MILNE EDWARDS (Crustacea, Brachyura) Reared in the Laboratory By Keiji BABA and Keisuke MIYATA Reprinted from the Memoirs of the Faculty of Education,