378 The Upper Elf Loch, Braids. [Sess. 



is rather a distinct and readily recognised form, and was not 

 at all rare in the September gathering referred to ; yet, strange 

 to say, the only time it has with certainty been noticed since 

 was in the last gathering of the series, collected on the 23rd 

 April last, when only one or two specimens were obtained. 

 It may be stated in passing that Canlhocamptus inornatus 

 has also been recently, and for the first time, observed in 

 Duddingston Loch. 



These, then, are a few of the facts bearing on the distri- 

 bution of the Entomostraca which our examination of this 

 miniature loch has brought to light. They indicate how 

 much interesting information a regular and systematic re- 

 search, even of a very limited area, may yield. The curious, 

 and apparently erratic, appearance and disappearance of the 

 species we have specially referred to explains also to some 

 extent why one collector may be more successful than another, 

 or why the same collector may obtain a richer gathering at 

 one time than at another. 



As the study of the Entomostraca is now receiving greater 

 attention, and many microscopists and pond-workers are doubt- 

 less desirous of becoming more familiar with them, the follow- 

 ing notes on their reproduction may be of some little value 

 to such amongst our own members. The reproduction and life- 

 history of the Entomostraca have long engaged the attention 

 of naturalists, and are still subjects of considerable interest to 

 students of these crustaceans. The Cladocera, one of the 

 more important orders of the Entomostraca, is of special in- 

 terest, because of the peculiar reproductive processes observed 

 in several of the groups composing the order. Most part of 

 the Cladocera are fresh-water organisms : a few of the genera, 

 however, are marine, and species belonging to these marine 

 genera are sometimes observed in immense numbers, so that 

 the lack of variety in marine forms, as compared with those 

 inhabiting the fresh waters, is somewhat compensated for by 

 the greater number of individuals that are occasionally met 

 with. 



All, or nearly all, the fresh-water Cladocera produce two 

 kinds of " eggs " — viz., summer eggs, and winter- or resting- 

 eggs. The summer eggs are considered to be, not true eggs, 

 but " buds," and they have received the name of " pseudova." 





