406 Sidney I. Kornhauser 



sally behind the fifth swimming legs. The egg sacks are carried between 

 the shield-like portion of the thorax, which oveiiaps the abdomen, and 

 the large fifth swimming legs, to which they are firmly attached. When 

 the egg sacks are first foriiied, the eggs are a much deeper red or orange 

 than in their later development. 



V. Spermatogonia and Oögonia. 



A. Spermatogonia. 



In a study of the entire literature on Copepods, one finds very little 

 concerning spennatogonial and oögonial mitoses. Even in the more 

 recent works, with the exception of Chambers ('12) and Krimmel ('10), 

 we see no metaphase plates figured. Moroff ('09), in a work in which he 

 treats the phenomena of the maturation of copepod eggs entirely from 

 the Standpoint of a protozoan investigator, and who lays no significance 

 on the phenomena of niitosis or tetrad formation, found in his preparations 

 no karyokinetic figures in the multipHcation zone. He therefore thinks 

 it probable that multipHcation takes place by amitosis. His figures 

 (40—42, Taf. XXXV) are far from convincing; and since all other workers 

 on Copepods have found spennatogonial and oögonial mitoses, it is not 

 likely that they are absent in the forms of the Triest plankton. 



The problem however is not mitosis or amitosis, but the relation of 

 the chromosome number in the spermatogonia and oögonia to that in 

 the spermatocytes and oöcytes — a question which Rückert, as early 

 as 1894, discussed for the Copepods because the works of Ishikawa ('91) 

 and Haecker were not in accord with his own results on Cyclops. Mat- 

 scheck ('10), after quoting vom Rath '95 as to the unfavorablenessi) of 

 the oögonia and spermatogonia for study, gives slight evidence (Textfig. 15) 

 that the haploid number occurs in the oögonia, as vom Rath ('95) found 

 for Änomalocera, and questions the result of Lerat ('05), who Claims 

 the diploid number of chromosomes for the oögonia and spermatogonia 

 of Cijclops strenuus. 



In Hersüia all stages in the multipHcation of -spermatogonia and 

 oögonia could be seen. Immediately behind the "Keimpolster" and 

 before the bend of the testis are the karyokinetic figures, never in the 



1) Lerat and McClendon State that the diploid number of clKomosomes appear 

 in the spermatogonia, but do not give figures. Krüger states that coiinting was im- 

 possible, the chi'omosomes of the oögonial metaphases being massed together in a solid, 

 deeply staining plate. This is probably due to fixation with subhmate, which is suitable 

 only for eggs in advanced growth period or in maturation or cleavage. 



