It is well established by previous workers that the glandular component of the pituitary in teleosts is derived from the ectoderm of the buccal cavity. Haller, Matthews, and Kerr have obsorved that the first appearance of the pituitary in all teleosts is as a solid ectodermal inpushing of the buccal epithelium, without any cellular differentiation, which extends below the brain and bocomes stalked

Tampi, P R S

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Pituitary of Chanos ehanos (Forskal.' IT is \ve11 established by previous workeJ:s that. t.h~ glandula,r component of the pituitary in teleosts is (lerived. from t he ect oder m of the buccal cavitv. H a llerl , Matthows2, and ICerr~ have obsorved that. the first appearance of the pituitary in all teleosts is IlS a solid ectodermal inptlshing of the bUCCAl epit helium, without a ny cellular differentiation, which extoncLq below the bn:tin and bocomes stalked. This does not at any time possess a hypophyseal cavity. Studies made on ,the fry and fingerlings of Chano$ chanos show, howovp.r , a noteworthy peculiarity in t his species. Tho cn.l'l iest stage of ()hanos o.va,ilable to me \vas 14 rum. in total length, und may be estimated as t iu'ee to four weeks old". Tho pituitary at t his stage hns an elongated appearance measw'ing about 325 tJ. X 70 P. X 50 fL. A blind d iverticulum is seen starting from the roof of the mouth just in front of the begllllling of the branchial arches, s loping posteriorly and tel'rninating dorsally at the ant(,l'j("ll' end of tho hypophysis. The cells fl'OID this blinu. ond of the clivertiuulum proliferate t o give ri se to the glandular elements of the pituitary. '1'0 begin with, all the cells of the glandulru' component ar~ basophilic, but later some of them become acidophilic or even chrom ophobic in the various regions. ~o '252 April 28, 1951 NATURE a:::ittnJ section of CII4M. la)"va. (U mm.) shnwlng tim diverticulum from Ole I)IICClli c.wity (;ormectiOl{ it with the pjtllitaJ·~· The point of interest is Lhe cnnnuxion of tho anterior :.ld of the p ituitnry (photom icrograph, p) with tho )Ucc'al cavity by means of the diverticuhllTI (d). [his connoxion with the hucct'L1 cavity is rctaulrd mril a c()mparativol~t late stago iu the life of tho j- ... . hut ~oerns to cli.''$appear in fingerlings of Heal'll' ",,""1 nun. leu6Tth. Although a continuotls passage from :c. "mouth to the pituitary is not appurent in the later -tages. vestiges of the connoxion pel'sist closo to the r.ypophysis even in fish measuring 200 mm. ill Lotnl «ne-th. I n long~r fish, howover, the I'emainf.: of the dh"el'ticulum u o longer show 0. well·defined cellular epirholiallining but only a shoot of connective t isane. Wbrll. tho lurva grows to about 53 mm. in length, the unterior lobe of tho hypopJtysis develops cavitje"l by tho outpushing of t h o surface of tho rlivortioulnm. These hypophysool ca.vil,jes appear to be derived from the lumen of the diverticulum, which i tself is a ." ,ntinuntion of the buccal cn.v ity. Ptevious aceount,.", of the developmen t of the pitllitary in teleosts have shown that tho embryonal cOlUlexion of th e pituitary with the buccal epithelium disappears irrunedit~te l y after hatching; fol' example, in Salow tnlltrt, OlHpea hm'CJlY1l8 a.nd Salvel1'H1.18 lI' il/uyhbyii3. 1.'110 IT lde of or ig in of the cavjties in thf:' anterior lobe ( tbo piLuitu.I'Y in Lhesa is )10L clearly known. DrI,a,j1s of t IllS worK will bo submitted for publica. t ion elsewhere . :.\£y thunks are duo to D1'. N . K. Pan ildmr, chief res6Rl'ch officel', CentJl'nJ Mt'\.l'inc FishcrieR Station, for his help in th o preparation of thiR 'lote. Central )Iarino Fishuries St.at ion . Mo.ndapam Cnmp P.O., :Sooth India. Nov. 10. I Haller. B., Morph. JIUlrb •• 25 (J.::o96). 1 )btt,hew;;, S. A. , Biol. !lull., 13 (193;). P. R. S. 'l ',Dr!'t I Kerr. 'r., Prac. Rr.y. Soc. Ellin .. 60 (l040) • • :-idIll11 :.' r. W. [i. , "Dcl)t. v:ln ] .:trldbouw ell \·IAAerij. , ])ub. _'10. 2, " '1m d~ OudcratUelill:: UiUlU'Uri!'.St·rij (lU~D). 087 -. 

Pituitary of Chanos chanos (Forskal)

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Pituitary of Chanos chanos (Forskal)

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