166 MR JAMES MURRAY ON 
Family PLasomap&. 
Plesoma truncatum (?) Levander (29). Frequent. Plesoma triacanthum(?) Bergendal (3). Lochs Oich 
" hudsoni, Imhof. Frequent in N. Uist. and Uanagan. 
Family GasTROPoDID®. 
Gastropus stylifer, Imhof (23). Common, noted in about 70 lochs. 
Family ANAPODIDA. 
Anapus testudo, Lauterborn (28). Lochs Ness, Huna, and Uanagan. 
Nores ON SOME OF THE SPECIES, AND DescrrpTions oF NEW SPECIEs. 
MELICERTAD. 
Melicerta.—Kmpty houses of species of this genus were found adhering to plants in 
Lochs Ness and Ruthven, but no living example was seen. 
Pseudacistes rotifer, Srpnroos ? (Plate V. fig, 18) (48), a gigantic free-swimming 
Rhizotan found in the shallow water of Inchnacardoch Bay, Loch Ness, is doubtfully 
referred to this species by RousseLer, who has only seen my rough sketch of it. It 
has much resemblance to C¥czstes velatus, Goss, but is much larger, and has the eyes 
quite differently situated. 
Mr RovusskLer informs me that Dr Couiins figured and described a form having 
the eyes near the edge of the corona, and has himself collected such an animal in 
Dr Co.utys’s favourite pool near Sandhurst. He adds that the eyes are seated on an 
elevated cushion, a feature shown in my sketch. Our animals were larger than any 
which StenRoos measured. Total length, 925 « (STENROOS, 750 «) ; length of trunk, 450 « 
(StenRoos, 280 «); diameter of corona, 295 » (STENROOS, 220). Our measurements were 
made from free examples, SreNRoos’s from sessile individuals, and the trunk is therefore 
more extended and narrower relatively in ours; the measurement of the corona is less 
in excess of his. 
My drawing may be taken as a faithful representation of the general form and 
proportions, and of the viscera as far as shown. The details of the head were less 
successfully observed, and I failed to make out the correct orientation of the parts. 
For these, STENROOs’s figure (48) may be consulted. The antennz were not detected. 
STENROOS figures the eyes within the corona; my drawing shows them outside the 
principal wreath. As Srenroos expressly says that the eyes are deep-seated, the 
difference may be optical, and due to the point of view. RoussELET says the eyes are 
on the ventral side. 
A very powerful, rapid swimmer, as it rushes across the field with the immense 
hyaline corona widely expanded, it is one of the most magnificent of Rotifers. 
