9 8 



SIEJI KOKU1ÏO : 



specimens collected near Kyoto have the three terminal joints of first 

 antennae provided each with an inconspicuous " Rudermembran " on 

 the inner border. The crenulation on the rami of furca is subject to 

 much variation, as it appears according to localities. 



The habitats in Japan known to me at present are : Kyoto and 

 Saitama in Hondo, and Sapporo in Hokkaido. 



2. Cyclops stremius Fischer. 



Pl. II, figs. 5-7, 

 Cyclops stremius Fischer 185 1. 

 Cyclops clausii Lubbock 1863. 



This is another common species of the genus in Japan. It occurs 

 in abundance in the muddy bottom of marshes and also in large lakes. 

 In Lake Shikotsu (Hokkaido) it appears in early spring and forms 

 the main part of its plankton fauna in that season. It may be worth 

 mentioning that specimens collected in shallow water are brown in 

 colour, while those from open lakes of clear water present a deep 

 red hue, as is known to be the case with Diaptomas denticornis. 



In Hokkaido, reproduction occurs in winter under ice, the nauplii 

 coming forth under the same circumstance. The nauplii are seen 

 most profusely in the months of June and July. In a laboratory 

 aquarium with water temperature varying from 19 to 23 C, I have 

 observed individuals laden with egg-sacs for the first time on January 

 31st (in 1910) ; and it was on the 5th of the following month that 

 the lavae hatched out from the eggs. 



The species has been recorded in Russia, England, Germany, 

 Holland, and Hungary. 



3. Cyclops magnoctavus Cragin. 

 PH. II, figs. 8—12, 

 Cyclops magnoctavus Cragin 1883. 

 This species occurs in early spring in the neighbourhood of 

 Sapporo. It is the smallest species so far known in Japan, the female 



