350 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



of the subject, although it may be noted that he is here inclined 

 to consider favorably the interpretations, especially of Pearl 

 and Correns, that these are definite Mendelian units accountable 

 for sterility and fertility. His analysis of their data is, however, 

 not critical and the view that cytoplasmic relations established 

 in a heterozygous individual are quite of the same nature as 

 similarity in heredity factors brought about by inbreeding is 

 equally suggestive that in the latter case the cytoplasmic relations 

 may also be the most important. 



In rather marked contrast to Morgan's results are those of 

 Fuchs ('14), which show clearly that Ciona iiitestinalis at Naples 

 is self- fertile to a "very varying degree in different individuals." 

 Fuchs, however, fails to see any relation of such phenomena to 

 that of self-sterility in plants like Reseda and Cardamine, chiefly 

 because he does not seem aware that here the same degree of 

 variation may be in evidence. Fuchs, further, considers that 

 cross-fertility is nearly absolute in his strains; the cases of poor 

 results are in general attributed to pathological conditions. His 

 actual results show, quite as do Morgan's, that there is a wide 

 range of variation in the fertility of different crosses. iFuchs' 

 experiments are scarcely convincing on this point as no adequate 

 number of individuals were tested with two or more individuals. 

 Numerous very critical experiments were planned to test various 

 phases of the physiology of fertilization in Ciona, but the number 

 of tests made were most frequently too limited for conclusive 

 results. Furthermore, these experiments as well as those of cross- 

 fertilization were made with individuals whose self-fertility or 

 self-sterility was not determined. The results, however, suggest 

 that the egg and the ovary extracts, and the blood of individuals 

 when added to sea water containing eggs and sperms of two 

 different individuals increase the percentage of eggs fertilized. 

 It is suggested that the eggs of self-sterile individuals give off some 

 substance that inhibits the sperm of that indi\'idual; but one experi- 

 ment was made to determine if egg extracts of an individual B inhibit 

 the action of the sperm of B on eggs of A (Fuchs, table VIII), 

 but the result shows no such action. In this experiment, how- 

 ever, it was not determined whether A or B were self-sterile. The 

 influence of egg extracts on self-fertilization and cross-fertilization 

 between animals of similar or of different grades of self-fertility 



