332 Toyama, Mendel',- laws of heredity as applied to the silk-worm crosses. 



floss very small) breeds, the cocoons produced in the lirst cross 

 are generally spindle shaped except a few which are elongated oval 

 or ellipsoid. 



The second generation derived by pairing inter se was, however, 

 composed of a diversity of forms, of which spindle-shaped, oval or 

 ellipsoid forms were most abundantly formed. Some of them had 

 a constriction in the middle and there was no Japanese oblong 

 form. Besides those above enumerated there were many inter- 

 mediate forms which could not be separated from one another. 



Of these, some such as oval or ellipsoid became nearly con- 

 stant after the selection of several generations. On the contrary, 

 the spindle-shaped form became hardly constant, so it always pro- 

 duced some other forms. The Japanese oblong form appears to 

 behave very rarely as an active character, so it was impossible to 

 nie to trace its hereditary behaviour. 



According to our experiences hitherto obtained through a long 

 series of generations, we may say that of those forms above 

 enumerated, the spindle-shaped or conical form predominates over 

 others. Next ranks the oval or ellipsoid form and lastly comes 

 the oblong or cylindrical form. 



The brood characters. 



(such as uui-, di-, tri- or multivoltiue etc.) 



The reciprocal crosses between multivoltine and univoltine 

 breeds or univoltine and divoltine breeds gave, in the first crosses, 

 pure maternal offspring, sometimes pure paternal, rarely a mixture 

 of both parent-characters, as the following tabular Statements show: 



A. Japanese univoltine $ X divoltine 5. Eggs laid all di- 

 voltine. 



B. Japanese univoltine $ X divoltine S. Eggs laid all uni- 

 voltine. 



I. 



II. 



III. 



IV. 



A. European univoltine yellow 3 X Japanese divoltine §. 

 Eggs laid all divoltine. 



B. European univoltine yellow g X Javanese divoltine S. 

 Eggs laid all univoltine. 



A. Japanese univoltine 5 X divoltine S. Eggs laid all di- 

 voltine, or paternal. 



A. Japanese divoltine 5 X Siamese multivoltine S. Eggs laid 

 all multivoltine, or paternal. 



B. Japanese divoltine $ X Siamese multivoltine 5. Eggs 

 laid all univoltine, or paternal. 



Both of these cross-bred forms do not breed true to parents 

 bot split again into their parent-characters in the subsequent gene- 



