CHONDRIOSOMES IN THE CELLS OF FISH-EMBRYOS 



J. DUESBERG 



Carnegie Institution, Department of Embryology, Baltimore 



EIGHT FIOURKS 



Since ^Sieves' ('08) discovery of chondriosomes in the cells 

 of the chick-embryo, these cytoplasmic elements have been found 

 in the embryonic cells of other birds, of mammals and of am- 

 phibians among the vertebrates, and of insects, of worms and of 

 ascidians among the invertebrates. The only description of 

 similar structures in embryos of the lower vertebrates (i.e., 

 fishes) has been given by Aunap ('13), in his paper ''Ueber die 

 Chondriosomen der Gonocyten bei Knochenfischen." Aunap, 

 as the title of his paper indicates, was especially concerned with 

 the study of the primordial germ-cell. His purpose was to find 

 out whether, in Coregonus maraena, as Rubaschkin ('10) and 

 Tschaschin ('10) had described for mammals and birds respec- 

 tively, the chondriosomes of these cells were granules — a point 

 to which Rubaschkin was inclined to ascribe great theoretical 

 importance. Confirming the above mentioned authors, Aunap 

 found only granules in the primordial germ-cells. In the other 

 cells of the germinative epithelium, however, as well as in the 

 epithelium of the intestine, of the neural tube, and of the Wolf- 

 fian ducts, filaments were present. In younger stages (i.e., in 

 the blastomeres), Aunap found granules exclusively. 



I have had the opportunity of extending these observations 

 b}^ the study of embr^'os of several species of fishes: the white 

 perch (^lorone americana), the yellow perch (Perca americana), 

 the rainbow trout (Salmo irideus) and Fundulus heteroclitus. 

 The first three of these were obtained through the courtesy of 

 the L^nited States Bureau of Fisheries from the hatcheries at 

 Havre-de-Grace, Maryland, and White Sul])hur Si)rings, West 

 Virginia. For Fundulus, I am indebted to the Biological Lab- 



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