38 
tentacles, I found them ear-shaped, pointed, grooved laterally, and 
the papillz on the surface sub-retractile. When placed in a jar of 
water a tubular whitish organ would protrude from the central aper- 
ture and act as asucker. Mouth probably anterior at the base of the 
tentacles. It is very active, and swims rapidly. 
4, Prasta macu.ata (Pl. LXX. figs. 7, 8). 
Body oval, smooth, thin, flat above and beneath. Without foot or 
tentacles. Margins rather thick. At the anterior end there are two 
strong folds of the body. Colour above yellowish-fawn or greenish- 
slate, orange towards the margins, and covered with circular greenish- 
slate spots, encircled with white rings. 
This animal is very active, swimming by the undulations of the 
body. When in motion it has an oblong-oval form, and when at rest 
a rounded ontline. The folds in the anterior portion of the body are 
analogous to the grooved oral tentacles of Aplysia. 
5. Peasta rrrorata (Pl. LXX. figs. 9, 10). 
Body smooth, elliptical, thin, flattened, and rounded similarly at 
both ends. No foot or tentacles. The cluster of dots is microscopic 
in size and oblong in shape. Two orifices beneath, a little anterior to 
the middle ; the anterior one has lateral radiations, or white appen- 
dages, under the surface ; there extends anteriorly from this orifice 
an elongate tube beneath the skin, which does not quite reach the 
anterior margin ; this vessel the animal can retract and extend. 
Colour above pale yellowish-fawn, irregularly dotted with brown and 
white, and densely minutely punctured with fawn. 
Length ? inch. ; 
This species is very active, creeping by very slight but rapid un- 
dulations of the body, and also floating, back downwards, on the 
surface, and moving about in that position. 
6. Furtuer EvipENCE OF THE DISTINCTNESS OF THE GAMBIAN 
AND Riipre.y’s SpuR-wINGED GEESE (PLECTROPTERUS GAM- 
BENSIS AND P. rtppeviit). By Pure Lutriey Sciater, 
M.A., SECRETARY TO THE SOCIETY. 
The recent death of the males of the two species of Spur-winged 
Geese (Plectropterus gambensis and P. riippellit), of which I pointed 
out the external differences at one of last year’s meetings * of the So- 
ciety, has given me the desired opportunity of comparing the trachez 
and skeletons of the two birds, and showing that these afford ample 
corroboration of their specific distinctness. Before proceeding to do 
this, I should remark that the individuals to be compared are both, 
as we know from their dissection, adult males. The specimen of 
P. gambensis is in all probability the older of the two, having been 
* See P.Z.S. 1859, p. 131. 
