1897-98-] The Upper Elf Loch, Braids. 375 



seven species. No representatives of either the Amphipoda 

 or Isopoda have been observed, though both Gammarus pulex 

 and Aselhis aquaticus are frequent enough in other parts of 

 the Edinburgh district. 



The greatest number of species observed in any single 

 gathering was twenty-five ; this gathering was collected in 

 September 1897. The smallest number — twelve — was 

 observed in a gathering collected in May 1896. Five species 

 of the Entomostraca have been observed in every one of the 

 twelve gatherings examined : the names of these species are — 

 Cyclops viridis, C. bicuspidatus, Canthocamptus staphylinus, 

 Cyclocypris serena, and Candona Candida. Two species — 

 Cyclops strenuus and Simocephalus vctulus — were observed in 

 ten of the gatherings. Three species — Cyclops serrulatus, 

 Alona quadrangularis, and Chydorus sphmricus — occurred in 

 nine gatherings. Attheyella pygmcca, Cypria ophthalmica, 

 Daphnia pulex, and Alonella nana — four species — were ob- 

 tained in eight gatherings. Attheyella crassa and Alona guttata 

 occurred in seven gatherings, Cyclops albiclus and Cypris fuscata 

 occurred in six, and Ilyocryptus sordidus in five. Cyclops 

 vernalis, C. fimbriaius, Moraria Anderson- Smithi, and Grapto- 

 leberis testudinarius were observed in four gatherings ; while 

 Canthocamptus minutus was obtained in three. The following 

 eight species were each observed twice — viz., Cyclops fuscus, 

 C. affinis, Canthocamptus inornatus, Attheyella Zschohkei, Piono- 

 cypris vidua, Geriodaphnia retiadata, Alona costata, and Chy- 

 dorus barbatus. 



"With regard to the seasonal distribution of the Crustacea 

 the following points may be noted. It has been already 

 stated that five of the species obtained in the loch occurred 

 in every one of the twelve gatherings examined. These 

 gatherings were collected under very varying conditions of 

 weather and temperature, as well as at different seasons of 

 the year — for example, during the heat of midsummer, when 

 the little loch was much contracted by drought and largely 

 overgrown with vegetation ; during the late autumn, when it 

 was filled to overflowing with the autumnal rains and when 

 the vegetation had to a considerable extent disappeared ; and 

 also during winter, when the only way in which a gathering 

 could be taken was by breaking the ice that covered the 



