Sludius oil iiiaiiiii' Ostracods 355 



The samples on which this table is based were taken at Spitzbergen and Greenland, thus 

 from two places with rather similar external physical conditions. 



It must be pointed out here that the figures in this table state only how many 

 specimens were closely investigated by me. They must, on the other hand, by no means be 

 considered as statements of the approximative proportions between the categories of the 

 table. The samples in question were certainly rather incomplete; they had — if I am 

 not mistaken — not been collected for quantitative investigations. In addition it iiiay 

 be mentioned that in some cases only a portion of the individuals found in the samples 

 were investigated. 



Several hundred additional specimens of this species from other samples were investigated. 

 As, however, these investigations did not give any results beyond what are already shown in 

 the above table, they were not included in it. 



Mature females: In the first column of this table are included such 

 females as have no eggs in the brood chambers, have very small eggs in the ovaries and have 

 their natatory bristles on the exopodite of the second antennae broken off. They are specimens 

 that evidently had recently laid a hatch of eggs. This is shown by the fact that the posterior 

 2)arts of their bodies are pressed forward in the same way as in the females in whom the brood 

 chambers are filled by the voluminous collections of eggs. — • In the second column are 

 included females whose brood chambers are filled with eggs; these eggs are often of rather 

 different sizes in females of the same sample; the ovaries of these females contain very small 

 eggs and their second antennae are distinguished by having their natatory bristles broken. 

 The majority of the sexually mature females often seem to come into this category. — The 

 females of the third column have no eggs in the brood chambers, have eggs in the ovaries 

 and have the natatory bristles of the second antennae broken off. These females are distinguished 

 from the females in the first column by not having the backs of their bodies pressed forward 

 as in the females with their brood chambers filled with eggs. The eggs in the ovaries 

 of these females are more or less developed, often very small. — The females in the fourth 

 column are also without eggs in their brood chambers, the posterior parts of their 

 bodies are not pressed forward as in the females of the two first categories; they have 

 very small eggs in their ovaries and are characterized by long (unbroken) natatory bristles 

 on their second antennae. 



Mature males: These were always very rare in the bottom samples of this species 

 stored in the Swedish State Museum. They were quite absent from about eighty 

 per cent of all the bottom samples of this species investigated by me. The same state of affairs 

 has been observed by the preceding writers, both with regard to this species and other species 

 of this genus. Thus, for instance, W. Lilljeborg writes with regard to Ph. (Ph.) ylobosa. 1853, 

 p. 177, that among a very large number of females he observed only a single male. G. 0. Sars, 

 1865, pp. 108 and 111 says about this species that while females occur in very great numbers, 

 males are always extremely rare. 



Larvae: Among the specimens of the first and secc^id larval stage that were investi- 

 gated by me the females and males were about equal in number. 



