egg follicle, coD^'stiiig of but a single layer of* cells. At the time of 

 maturation, a fatty metamorphosis of the Cells of the granulosa takes 

 place, which promotes the escape of'th^ e^g froth the folliclie. The 

 micropyle is alwa5^s an open pore; it has a Very^vide external open- 

 ing and a very narrow inner one. The latter ends oh an internal prom- 

 inence of fhe' e^^-ffifeytitii^aVife, Whfc^^^^ -zyna' iftidaaljaV " ■ The lumen of 

 the internal micropylar opeuing'is'so constricted tliat not more than a 

 single spermatozoon can pass through at one time, as was first ob- 

 servecLbyHisiii the salmon, ^'i*^ 'io ladfji ^f^inhihv' ■ :; 



''It is well 'trhbwii that the gggsWinaiiy bony fi'^lie's- adhere to fixed 

 objects as soon as they fall into the sea-water. This is not always ac- 

 coihpl ishediu ' the '^aiiie wdy^ ''i&W^(MMs^ WMUis, '!Blmniiis','Bdlon&,eW. , 

 this is itCC6mplisfied''by fon'g'-*ffliihifc'tit^s; ts^cl^iscericeS^ of'the zoiia r?i- 

 diata, which are not distributed OA-er the whole Of that structure, but 

 which iare fouhd dnlj^ dii certm'n p6rti6'ii^l vife,'fn the 'vicinity of the 

 micropyle.' 'lii' the herring and CremtaJii^its'tli^ wTiole of the Sui^face of 

 the egg is 'covered ifith an adhesive material. In the case of' all ova 

 which attacli tiiemsfelvey by these contrivances, the zona consists of two 

 layers, ati'iuhet a'rid an biiter one, the hitter beibg Vidhesive, and split 

 off from the former to embrace the whole egg, or is developed ^n the 

 form of fibers, ik'dcesses, and similar appendages. In contrast with such 

 forms, those OVa which float or sink to the bottom, of their own weight, 

 do not seem to have siich a differentiation of the zona into two' layers. 

 It is highly probable that the zbiia is a secretion from the siirf'ace Of 

 the ovarian egg, and that it is to be reigarded as a vitelline membrane. 



" The primordial 'bv^'cdif^st cif a 'hombgeueoiis mass,' ' doagulable 

 in acetic acid, when it becomles' granular, and they inclose a large nu- 

 cleus and a single large nucleolus. In very young oVa, of -which the 

 contents ai^e siimlar t0l;tie4'bre^oiiig;'seveM nuc^oli' fMy^ali^^dy^^be 

 discerned in the iuicieu'sf "In" the ova designexl for the next brood, the 

 yelk corpuscles are grEtdually developed, until they finally occupy the 

 whole mass Of the egg excbpt tlie spac^ ta&fehiJp'by'tlie' fiu^Mij^j aind 

 only the sinair spaces between the gi'anules ah^' coi^puscles are 'filled 

 up by the protoplasm still present. The yelk granules and corpuscles 

 consequently appear to be developed Vit the cbst 6f 'the' febnt!aitled't>fo- 

 tbplasm of the egg. The cells of the griahulosa'^ere never obserted to 

 give off protopWsinic processes passing inwards into the egg through 

 the pore-canijiij.'J ■'^'' J^"' '■"'^-■i^"''- J^> AioUJ:;.,^ iiiJ^i-^okiwA ^ilt U: .^.innsti^u 



■ '^" In the foregBMg^-^k^e'llP- Bt-& «^^s' ai%-diiTI'itiid^^oi)a{iVi:e'-- 'fevfen 

 H^e'^g^s of Scbrpwna, Julis, ^fermww^, and Fierasfer, of crystalline trilhs- 

 parency at m'atiirity, pass through the saine opaque 'stage of otarian 

 development. In the very large nucleus the nucleoli- ebiitifiitetcy mtil- 

 tiplyl^^ f^^sOiit dtiw B3i)in~ri\n\ smnisTt^JKlo 7m pl>:omu"''o <jj aA. '' 



'^Towards th^ tiiiie of maturity, the huclcns be'gius toitibVe frbiu its 

 oHginal central position to the periphery. During its change of poki- 

 tioUj'the smooth; fightly distended nuclear membniue cbmmenees to 



