AND TWELVE NEW SPECIES OF ROTIFERA OF THE ORDER BDELLOIDA. 3838 
prominences. Space between discs equal to half diameter of disc. Rostrum short, 
shaped like an acorn, basal joint papillose. At back of oral segment, on each side of 
rostrum, a large rounded papillose prominence. Length of antenna equal to diameter 
of neck. Neck with rounded prominence at each side of antenna. Foot of three joints, 
stippled. Spurs small, tapering, divergent. Dorsal toes tapering; ventral larger, obtuse. 
Two teeth on each jaw. Oviparous. 
General description.—Greatest leneth when creeping, 7} to 74> inch. Skin of 
trunk dull yellowish-gray, opaque, finely stippled, foot more strongly stippled. The 
prominence from which the central seta arises occupies nearly the whole of the upper 
surface of the disc. The great papillose bosses on the back of the oral segment are 
unique. They are conspicuous when the animal is creeping as well as when feeding. 
‘The skin of the first foot-joint is thickened dorsally, but does not form a boss. 
Related species—This species is closely related to Philodina alpium (Callidina 
-alpvum, Ehr.) and P. brycez, (C. brycer, Weber). The three species form a very natural 
group. ‘They are semi-loricated. The skin of the trunk is thick. Its anterior edge is 
-eut into definite forms and bears six knobs or processes. Its ventral surface is crossed 
by deep transverse folds, 9 to 15 in number. Though not quite rigid, it alters little in 
shape. When the animal is fully retracted the deep longitudinal folds allow the 
anterior edge of the trunk to be closed. In P. alpwwm and P. bryce: the two anterior 
dorsal processes of the trunk form a fork which receives the antenna, as in Anurea and 
Brachionus. In all three species the central sete rise from large conical processes. 
There are four toes. 
Habits.—Like its relatives P. alprwm and P. brycei, it is very slow in its move- 
ments. When it has been left undisturbed for a time it feeds with confidence. It 
ceases feeding at short intervals, but resumes again at the same spot. 
Habitat.—Found in ground moss and Frullania growing on stones. Old pier at the 
Monastery, Fort-Augustus, 7th February 1904. At several spots near Fort-Augustus. 
Not yet seen anywhere else. 
"TRANS. ROY. SOC. EDIN., VOL. XLI. PART II. (NO. 15). 56 
