432 



Sidney I. Kernhäuser 



primary oöcyte (haploid number) will be given, since these counts can 



be considered most accurate. 



[The number of chromosomes is indicated by the numerals following the 

 name of the si3ecies, the word "chromosomes'- being omitted. Unless otherwise 

 stated, they are tetrads of ordinary form. The authorities upon which the coimts are 

 given are designated by the following abbreviations: Braun — B; Chambers — Ch; 

 Haecker — H; Korxhauser — K; Krüger — Kr; Matscheck — M; McClendon — 

 McC; RücKERT — R; vom Rath^ — v. R: Steuer — S.] 



I. Calanoida 



Calanus gracilis . . . 



Euchaeta marina . . . 

 Diaptomus denticornis 



» salinus . . 



gracilis . 

 castor . . 

 laciniatus 

 coeruleus 



sp. 



Heferocope weismanni . 

 Anomalocera patersonii 



16 



17 

 17 



"I 



17 

 17 



16 

 14 



8 



16 

 16 



large, in the form of rings, all practically the 

 samc size. Before the spindle is formed they 

 are also rings. K. 

 large rings. K. 

 M. 



rings which are somewhat flattened in the ger- 



minal vesicle. 



M. — 16 R. Rings all of same size. 



(14 + 1 composed of 3 rings, potentially 17) M. 



M. 



rings all of same size. ]\I. 



dumb-bell shaped — a Japanese form described 



by Ishikawa. 



rings. R. M. 



rings of equal size. v. R. 



The Chief characteristics of this group are that the chromosomes 

 appear usually in the number sixteen or seventeen, that they are large, 

 practically all of the same size, and almost withoiit exception, ring-shaped 

 both in the first maturation spindle and in the germinal vesicle tONvard 

 the end of the growth period . So far no small chromosome without "Quer- 

 kerbe" has been described in this group, and the only extraordinary chro- 

 mosome is the multiple form composed of three tetrads which was found 

 in Diaptomus castor. The Japanese Diaptomus (species not given) does 

 not conform with the general type of the Calanoida either in the form 

 or in the number of its chromosomes. 



IL Harpacticoida. 



Canthocamptus staphylinus 12 



» irispinosus 



Niiocra Inier nica . , . 



11 



all practically same size in spindle, in the form 

 of parallel rods, not rings. In germinal vesicle, 

 sometimes in the form of a cross or ring, but 

 generally parallel rods. H., M., Kr. 



[(2, large; 8, medium; 1, small: all with "Quer- 



[ kerbe". Kr. 



j small, without evidence of a Querkerbe in 



(spindle. Kr. * 



