THE ROTIFERA OF THE SCOTTISH LOCHS. 183 
NoroMMaTA PUMILA, n. sp. By C. F. Rousseter, F.R.M.S. 
(Plate VI. figs. 25a to 25c.) 
Specific characters.—Body stout, elongated, plump and rounded dorso-posteriorly ; 
the head remarkably small, less than half the width of the body immediately behind it, 
tubular, and surmounted by a tuft of vibratile cilia, without auricles or other prominences ; 
small clear brain with small cervical eye on the under surface near its posterior extremity. 
Foot stout and rounded, carrying two small, pointed, slightly recurved toes, deeply 
shouldered on the dorsal side of their extremity. Size—length, 127 « (s}, inch); 
width, 54 « (z+, inch); toes, 14 u (z_yp inch). 
Habitat.—Amongst moss in Caledonian Canal near Fort-Augustus, Scotland. 
I found this species in November 1904, by washing out damp moss kindly sent to 
me by Mr James Murray from the Caledonian Canal; but it appears it had previously 
been observed in January of the same year by this gentleman, and I could readily 
recognise it from his sketches. 
The peculiar formation of the small tubular head gives the animal a striking aspect, 
which is only shared by Miss Guascorr’s Notommata gigantea, with which it has 
indeed considerable resemblance ; and if it had not been for the peculiar structure of its 
toes and its diminutive size, | would have been inclined to refer it to that species. 
The integument is white, transparent, soft, and yet with a certain amount of 
stiffness, so as to always maintain the animal’s shape. Posteriorly, a broad triangular 
fold indicates the beginning of a stout, jointless foot, which carries two short recurved 
toes, of peculiar and characteristic shape, distinctly and deeply shouldered at the 
extremity ; an enlarged figure of the toes is given in fig. 25c. 
A clear brain of moderate size carries a small red eye on its under side. 
The mastax is of large dimensions for the size of the animal, and contains powerful 
and complex jaws of forcipate type (fig. 25b). The manubria in particular consist of 
two separate chitinous rods on each side, and joined at their extremities. I do not 
remember a similar structure in any other Rotifer. The unci are broadened plates, 
apparently without teeth—at least | was unable to detect any. Above the unci were 
seen some apparently loose and curved chitinous rodlets, which remained in position 
after dissolving the soft parts with caustic potash. The rami are small, and their exact 
shape and structure dificult to observe. In fig. 255 I have represented what I was 
able to make out of the incus; the fulcrum is a narrow and short rod, curving 
inwards and broadening at its base. 
Dorsal and lateral antennze are present in their usual positions. A large stomach 
and intestine fill the greater part of the body cavity ; the other organs are quite normal 
and call for no detailed description. 
Notommata gigantea, with which I have compared this new species, is vastly 
larger, reaching 726 m (34; inch) in length, according to Miss Giascorr, has very 
small toes, which are not shouldered, and the mastax also is small and apparently 
TRANS. ROY. SOC. EDIN., VOL. XLV. PART I. (NO. 7). 25 
