260 
BATHYMETRICAL SURVEY OF 
Loch Duhh . — This little loch, remarkable for its great relative depth 
and temperature conditions, resembling those in a great lake, was 
examined on two occasions. On the first visit in July, 1902, the surface 
temperature was 59° Fahr., while on the second visit in March, 1903, 
the temperature throughout was about 41° Fahr. Notwithstanding 
this difference in temperature there was little difference in the animals 
observed on the two occasions. Those found in July were : Diaptomus 
gracilis (blue and red, grey, red, blue), Cyclops strenuus, Bosmina 
obtusirostris (small, purple), Daphnia lacustris (all pale red), Eurycercus^ 
Polyphemus, Triarthra, Polyarthra, Anurcea cochlearis, Gonochilus, 
Ceratium hirundinella, Dinohryon. In March all the same animals 
were found, except Polyphemus, and there were in addition a few larvae 
of Gorethra (phantom larvae), Notlwlca foliacea, a second species of 
Geratium (G. cornutum — less common in lakes), Mallomonas. A very 
small form of Asterionella occurred. Near the shore large spheres of 
Ophridium were found on the weeds. In the mud from the bottom were 
many Rhizopods of the species Gyplioderia ampulla, Diffiugia pyri- 
formis, D. glohulosa, and D. arcula. T^ohelia and Myriophyllum were 
growing along the shores. 
Loch na Creige Duihhe . — As this loch was only examined by means of 
a net thrown out from the shore, it is probable that some of the pelagic 
animals may have been missed. The animals seen were : Diaptomus 
gracilis (reddish), Cyclops strenuus (yellow), Alonopsis elongata, 
Ghydorus sphcericus, Anurcea cochlearis, Bosmina obtusirostris, Arcella 
vulgaris. A few of the commonest filamentous Algae and Desmids were 
seen. Asterionella was scarce. 
