Apsilus and other American Botifera. By Dr. A. C. Stokes. 277 
Copeus quinquelobatus sp. n., plate YI. figs. 10 and 11. 
Body pale yellowish, flexible, very changeable, normally elongate - 
subcylindrical, posteriorly ventricose ; when contracted, subglobose or 
often with an anterior and a posterior, short, truncate, subcentral 
projection ; tail-like prolongation conspicuous, cuticular, subcylindrical 
and surrounding the foot sheath-like, ventrally oblique, the dorsal 
region being longer than the ventral ; foot soft, flexible, apparently 
of but one joint ; toes two, furcate, conical, acute, slightly decurved, 
about one-third as long as the foot, the proximal region flexible ; 
foot and toes together about one-sixth as long as the body, entirely 
retractile ; auricles present, seldom protruded, but large, elongate, 
somewhat recurved, obtuse, their frontal border densely ciliate ; face 
continued posteriorly on the ventral surface as a flat, densely ciliated 
surface, hut not protrusible into a lip ; lumbar sense-organs small, 
each terminated by a cluster of several fine, long, radiating setae ; 
dorsal antenna single, with a terminal cluster of fine, radiating 
setae ; brain enormous, multinucleated, with five elongate lobes, the 
central one clavate, about one-third as long as the body, and bearing 
a large, red, plano-convex eye near the frontal termination of its 
stem ; mastax large, broadly ovate, trophi normal ; oesophagus long, 
conspicuous, dilatable into a wide, thin-walled tube ; stomach and 
intestine together more or less obpyriform, both internally ciliated and 
differentiated only when filled with food-particles, the surface with 
numerous golden-brown granules and refractive oil-drops collected 
into apparently cellular and glandular polygonal areas, visible only 
when the stomach is dilated by alimentary matter in the process of 
digestion ; intestine proper always with colourless walls, and never 
exhibiting the brown polygonal areas ; a bilobed, multinucleated 
gastric gland attached to each side of the antero-lateral region of the 
stomach ; ovary ventral to the stomach and the intestine, but rising 
on both sides almost to a level with the dorsal surface of the parts ; 
contractile vesicle apparently double, each vacuole large, ovoid, thin- 
walled, the whole extending below the intestine, and almost entirely 
across the body, as a centrally bilobed organ, in close proximity to 
the posterior body- wall; foot-glands elongate-ovate, multinucleate, 
granulate ; lateral canals forming two loop-like convolutions on each 
side, one near the ovary, the other near the gastric gland, five flame- 
cells (vibratile tags) visible on each, one being in the head, all, in 
face view, flabelliform, much compressed, the frontal border convex, 
apparently thickened, the lateral margins obliquely concave; longitu- 
dinal muscles numerous, large, coarsely striated transversely. Length 
of the extended animal, 1/53 in. 
Habitat, a shallow pool in a rocky wood near Trenton, New 
Jersey, U.S.A. Movements usually not rapid. Facial cilia short. 
The species differs from all forms thus far described in the 
enormous five-lobed brain with the great flexible club of nervous 
