1324 



FISH CULTURE 



Results of Experiments. 



Races bred 



Weight of cocoons obtained from 

 I ounce of eggs 



normal 



constricted 



with 



poorly 



developed 



points 



Average 



weight 



of a 



Ratio 

 between 

 weight 

 of silk 

 cocoon 



and 



that of 



chrysalis 



Pro- 

 portion 



of 

 constric- 

 ted 

 cocoons 



Var NO I . . , 



Var N" 3 



Var NO 5 



Var N° 15 



Var, acclimatised in .Spain . . . , 



Ascoli Piceno N° i , 



Ascoli Piceno N° 2 



Ascoli Piceno, acclimatised in Spain 



Milan , 



Milan, acclimatised in Spain . . , 



Perusa , 



Fuentes Tijola , 



Spanish with black adults . . . , 

 Campocroce Cross No. i . . . . , 



Campocroce Cross No. 2 



Campocroce Cross No. 3 



78653 g 

 79215 

 81 792 

 76 796 



73095 • 

 80 886 

 86280 

 76 181 

 76556 

 69 798 

 68 764 

 62 262 

 61 632 

 74633 

 74717 

 71 134 



4861 

 I 217 

 420 

 789 



1 535 

 415 

 671 



2504 

 3 221 



3 196 



2 041 



651 

 1307 



4 021 

 I 929 

 I 741 



I 065 



821 



I 607 



1 456 



2 184 

 846 



1 049 



746 

 846 



2 214 

 2 114 



I 914 



I 080 



784 



3S2 



3429 



1-976 g 



2.019 



2.132 



1-759 



1.983 



2.020 



12.240 



I 



!i.9io 



I 



2.150 



I 

 2.020 



2.092 



2.040 



1.987 



1.800 



1-750 



1-750 



5.8410.3 % 



5-838 1.5 



5.809 0.5 



4.761 I 



5.2182 



4.824 0.5 



5-415 0-75 



5-7583 



5-5204 



5.3504.25 



6.390J2.8 



5.94011 



6.1503 



5.88oj5 



5.66o|2.5 



5.330^2.23 



FISH 

 CULTURE. 



1002 - The Migration of Fish of the Genus Mugil, in the Lakeof Thau ( i ). — RouleLouk 



in Comptes- Rendus lies Seances de la Societe de Biolog-ie, Vol. lyXXIX, No. 11, pp. 322-525. 

 Paris, June 1916. 



The complete migration of these fish includes two displacements in 

 inverse directions, one outward, from the lake to the sea, the other inward, 

 from the sea to the lake. The outward migration takes place during the 

 second half of the summer (August and vSept ember) ; it is connected with 

 sexual development, the individuals passing out of the briny waters of 

 the lake into sea water being chiefly breeding fish, the genital organs of which 

 are already bulky. Their sexual maturation and spawning takes place at 

 sea. The inward migration occurs during the winter and the first half of 

 spritig, its principal movement lying between February and April. The 

 individuals then passing from the sea water to the brackish waters of the 

 lake belong to two categories : one are recently hatched fry from the spawn 

 resulting from ])revious (-)utward migrations ; the otb.ers are immature adults 



(i) SecalMj />. May ivi'>, N'u. 513. 



(/•:</. 



