THE CYTOPLASM IN HEREDITY 35 



fact that not only nucleus but also cytoplasm is contributed 

 by both the male and female cells in fertilisation. He 

 suggests that certain cytoplasmic structures, "chondrio- 

 somes" divide with the cell, and are handed on individually 

 from generation to generation. 1 Although he seems to have 

 demonstrated the presence of chondriosomes in the cells of 

 different animals and one plant, 2 such structures are not, as 

 far as we know at present, demonstrable in the case of a 

 great many, perhaps not in the majority. The chondrio- 

 somes demonstrated by Meves occur mainly in animals, 

 but cytoplasmic structures, which like the nucleus and 

 centrosome divide and grow and are handed on from one 

 cell generation to another, have long been known in plants. 

 They are known as " chromatophores," and although 

 characteristic of plants, have also been demonstrated in a 

 few animals. These, in the fully developed organism, are 

 differentiated into bodies which produce starch, chlorophyll, 

 and other pigments, and they seem at all stages to retain 

 the power of division. They appear, however, to be of a 

 different nature to Meves's chondriosomes. 



With regard to the experiments in the fertilisation of 

 enucleated portions of ova which are cited above, it must 

 be pointed out that these have since been to some extent 

 counterbalanced, or their interpretation modified, by other 

 similar experiments which have given different results. 



Godlewski fertilised enucleated eggs of sea-urchins with 

 the sperms of Crinoids. 3 These developed into embryos 

 (gastrulse 4 ) which possessed pure maternal characters only. 



1 Meves, F M " Die Chondriosomen als Trager erblicher Anlagen, Cytologische 

 Studien am Huhnerembryo," Archiv fur mikroskopische Anatomic und Entwick- 

 lungsgeschichte, Bd. 72, 1908. 



2 "tiber das Vorkommen von Mitochondrien bezw. Choudromiten in 

 Pflanzenzellen," Sonderdbdruck aits den Berichten der Deutschen Botanischcn 

 Gesellschaft, Bd. 12, Heft 5, 1904. 



3 Godlewski, E., " Untersuchungen iiber die Bastardierung der Echiniden 

 und Crinoidenfamilie," Archiv fur Entwicklungsmechanik, Bd. 20, 1906. 



4 Gastrula. This is a stage in the development of the embryo from the 

 fertilised ovum. At first the cells produced by the series of divisions that 

 follow upon fertilisation are arranged in a single spherical layer. It is as though 



