4^ EEPORT ettiOOMMISSIONER OF FISH AND FISHERIES. [jl 6] 1 



df VMfeli'Wpij^t^fK^bes tlie male pronucleus, becoinos more nearly roundy 

 and linally assumes the ovoidal form of a nucleus. Iutb« course; of 

 frtrtber developiiieiit the two prouueyi approach eacbotbex more closely, 

 and fmally blend together into one nuelena, which repi-esents that of 

 the first cleavage, and in its histological cbairacters is perfectly lite the. 

 l^-oiiuclfei; it is witlioufea waill^ and consistsoif finely granular, lalmosti 

 homogeneous matter." ,::;...- ;•.;;;■:;; ^ :■!:;• t'.„' ■:..,;,■. :i'.h>!<r;tt 



Schenk's account of the metamori:)hosis of t-be geriBinaltvesiclei oi the 

 raj^ ii8''Somfe1\^bat ilike that'^ GEllaeher's regarding) the t^oubfesfelp^ 

 that he does uot state that it is eliminated in a similar mannex'; Atex. 

 Sebultz asserts that the appear auoes seen by Solieiik are the result of 

 thef^'OtfOn of rea^gentSi^iiT .gIoIssv iiiuiana'^ GtiJ ot 'mUnniti 9.1 

 fe!>)i^oiI.ui d-lj^. y^ ir.^iUiH'^u, eili to in±!f iLil>/ phiui'j-r tpmiU "In o:.:a;.;j;:: 



iif.!-j»ii:'.; .i! niu-r:^. ii:j7. or ^jn -,-.i .m ,: ^^ n;;>iilw ffo;: ,.,::m: . :m, n :-.:y\v 

 n-^^7i|lready.xera^rlfp(lj,;.the,iyitellus. 9f,the.,p^d!i^,,^g^,^i3^,Qomppsed of a 

 thin external layer or pellicle of germinal. lE^^ti.^i'p. which incloses the 

 yjelk siibvStauce, which forms by far the largest proportion of the wlible 

 vitelline mass. The outer pellicle (Z>of^c/Art<i^ of CEllacher ; cowcAe i/i/er- 

 ?->«je'd{^iV^, Van Bambeke)may be regai'ded, as the prQto;fflasm from which 

 the germ is formed, while the contained yelk, which is broken dowii into 

 leucocytes during development and later endjryouic growth, is the deu- 

 tfypla^W. These structui^es are the honiologues of similar parts in other; 

 Teleostean eggs as well as in those of the Ghondrosteiy or sturgeons,, ?is 

 we perceive by the fiescription of the ova of the latter by Salensky, 

 The layer ^J*", and the contained mass ^.of Fig. 1, pi. I, correspond tdthjese 

 two ejlemeutary portions of the vitellus of the cod's e^g. . ■ 



: The formation of the germinal disk of the cod by a kind of amoeboid 

 ijiigi'ation of the peripheral germiuiil matter towards the lower jwle of 

 t^lieeggjs, one of the moat remarkable i)henomena in the history of the 

 deYelQpinent, of Teleosteau eggs which has hitherto been recorded. "Ifiie 

 amoeboid movements which accompany the development of the disk are 

 a\Oststrikiug,^an(l, cannot fail to arrest the attention of the observer, in 

 %]m$> ^u^Q<?jp.j!a§;^,pef5cepti^ble- thickening or accumulation of germinal 

 matter has gathered at the lower pole, the germinal i)rotoplasm mani- 

 fests sKitiye.changes of form, due to its contractility. These pass over 

 the incipient disk as waves of contraction, and accompany the process 

 o| d^yelopmenjiof .|ili,eidi^ii:lpn^,bef any sign of segmei^tation, has 



* In tliTs connection t tuay remark 'irhflt chromieaeifl, followed by alcohol, or tlie first 

 al6ne, -will sofnetiraes produee cliaiage'sin the yelks offish ova of a very reiuarkable 

 character. jLu illiistratioii, lirecall the alterations so iudnced in the yelksof the eggs 

 of the ijhcid. • Spmetinie-s, the effect ytrodttced by the sluiiikiug and coagnlatiou of the 

 denioplasru ^s tp, develpj) a coiaplex system of anastomosing canals and spaces, wliich 

 at first look like as if they were trnly normal featnres iu sections.' Further investiga- 

 tion has couTinced me that these tubnlar cavities are purely the result of the action 

 of- chihjtnit;' actd upon the pjoteids of the- yelk. Doubtless, sttuctures of tJiis Jdud 

 Ki*^ in%l6dj btber: iuvestdgatoiisjjixiiiiging/rdm ,93?,sei-vations r^h^ehai,'© uppiinegord^ ; \ 



