THE ROTIFERA OF THE SCOTTISH LOCHS. 161 
Several other species were found which we failed to identify. 
The commonest animal in these deeper dredgings was Diglena uncinata. The 
typical form of Dinocharis tetractis was rare; but a variety, having the foot-spurs 
nearly or quite obsolete, was abundant. Several forms of Hosphora differed more or 
less from the types of the two species mentioned. 
There is little difficulty in accounting for the presence of these species at such depths. 
They are all common along the shores of the loch. These shores in many places are 
very steep, and it is easy to understand how animals which feed among the mud may 
readily get deeper and deeper. They all feed on organic débris, and such food is 
brought in abundance to these depths by the rivers, or falls down the steep slopes. 
In Loch Rannoch, Philodina macrostyla was dredged at a depth of 85 feet, but no 
Rotifers were found in the greater depths of that loch. 
The abyssal region in Loch Ness can only be defined by negative characters ; it 
lacks the majority of the littoral species. The littoral fauna gradually thins out as we 
descend, till a certain depth is reached, beyond which only a few species survive, and 
these extend to every part of the lake-bottom. Thus defined, we may say that there 
are no abyssal Rotifers in Loch Ness, as no species extends all over the bottom, as do 
Cyclops gigas, Pisidium, Candone, and the rest. 
As Dr Penarp points out, in dealing with the Rhizopods (42), Scotland has many 
other lakes, and we may yet discover in some of these the abyssal fauna and the 
relict fauna of which we have as yet got no trace. Up to the present the indications 
are against this expectation: north (in Loch Ness) and south (in St Mary’s) there is the 
same abyssal poverty. 
DES OH SPECIES. 
Order RHIZOTA. 
Family FLoscuLaARIAD#®. 
Floscularia campanulata, Dobie. Loch Ness. Flosculartia mutabilis, Bolton. Loch Morar. 
3 ornata, Ehr. Stephanoceros eichhorni, Ehr. Loch Ness, rare. 
i pelagica, RKousselet (43). Widely dis- 
tributed. 
Family MEeLicerTaD®. 
(Beistes crystallinus, Ehr. Loch Ness. Pseudecistes rotifer, Stenroos (48). Loch Ness. 
5,  brachiatus, Huds. Loch Ness (abundant), Conochilus volvox, Ehr. Generally distributed. 
Loch Tay. 5 unicornis, Rousselet. Common every- 
»  serpentinus, Gosse. Loch Ness, one ex- where. i 
ample. 
