610 Proceedings of Royal Society of Edinburgh. [sess. 
Dr Penard enumerates about fifty species, five of which are 
Heliozoa, and the rest Rhizopods, one species only of the latter 
belonging to the Foraminifera, Adding the sixteen species 
observed by members of the Lake Survey, we have a total of 
sixty-six species of Sarcodina in Loch Ness. This is not a very 
formidable list, when we bear in mind that Penard has discovered 
in the lakes of Switzerland close on fifty species and varieties which 
are peculiar to these lakes, in addition to the many common 
species also found there. 
When Rhizopods are dredged from the bottom of Loch Ness the 
great majority of the examples found are usually empty shells ; 
those which contain sarcode are generally quiescent, and it is only 
by the exercise of great patience that one can witness the pro- 
trusion of the pseudopodia, and thus ascertain that the sarcode is 
really that of the Rhizopod, and not of some intruder. All the 
collections, however, were not in this condition ; on several 
occasions there was brought up from considerable depths (250 to 
300 feet) material in which Rhizopods were numerous, of large 
size, and were actively and voraciously feeding when examined 
immediately after the collections were made. Such nests were 
apparently small, and I was never able to get similar results by 
dredging again at the same spots. The Rhizopods found on these 
occasions all belonged to a few common species, the only 
peculiarities being their large size and great activity. These 
collections also included large numbers of Entomostraca, Rotifera, 
Infusoria, and larvae of Insects. These limited areas must 
apparently be well situated for the reception of numbers of un- 
witting migrants from the shore ; the large size of the Rhizopods 
seems to indicate that they are also favourable for the maintenance 
of animal life, probably by offering a plentiful supply of food. 
On 16th November 1903 the following species were found, all 
about twice as large as the average of littoral specimens : — Difflugia 
globulosa, D. pyriformis , D. acuminata , D. spiralis , Nebela collaris . 
and Quadrula symmetrica. Species of other groups than 
Rhizopods were not unusually large, which brings into prominence 
the greater variability of the Sarcodina. 
Origin of abyssal Rhizopod fauna. — Dr Penard has shown that 
there are in Loch Ness some species and varieties of Rhizopods 
