80 THE ROTIFERA. 
the skins of decaying alge, and other aquatic plants. It seems reluctant to swim in 
the open water; but yet can glide along, smoothly and swiftly, when it pleases. 
Three months had nearly passed, and I had met with no second example of this 
beautiful species, though examples of valga and semiaperta had been numerous. But 
then, in water from the same fruitful pond at Woolston, a specimen occurred, which 
seemed the counterpart of peta, except that the great brain was destitute, so far as I 
could discern, of the pink eye, which had been the most conspicuous distinction of the 
species. Presently, however, another appeared; and here the whole occiput was 
instantly seen to be radiant with the soft, rose-red tint; the eye, in fact, or at least its 
pigment, occupying, just as in my first example, the whole lower part of the ample 
cerebral sac. Hence I infer that the rosy hue, normally pale, may sometimes become 
so dilute as to be practically undiscernible.—P.H.G.] 
Length, ;}, inch. Habitat. Woolston Pond; Sandhurst, Berks: rare (P.H.G.). 
D. SEMIAPERTA, Gosse, sp. nov. 
(Pl. XXII. fig. 10.) 
[SP. CH. Body compressed, highest behind ; lorica with the dorsal cleft closed in 
front, gaping behind, the ventral edges apparently approximate ; eye frontal ; toes long, 
slender, recurved. 
In describing Furcularia gibba (swpra, ii. 43) I have spoken of the resemblance borne 
to that species by the present, a resemblance which extends to other species. 
D. semiaperta bears much likeness to D. peta, but is still larger ; it is, too, higher 
behind, and the brain has no pink colour. There is, indeed, a well-defined oval eye, 
of deep red hue, but of moderate size, and situate near the front (fig. 10b). The 
brain is large, descending far down the back of the neck, quite clear, and strongly 
defined in outline. The locomotive cilia appear set on minute eminences over the whole 
rounded front, making no wheels, but visible as a simple fringe. The trophi are 
unusually large (fig. 10d'). The lorica, though split all down the back, has the edges of 
the fissure in contact at first, so that only the hinder half is open, and this but narrowly. 
In a succession of fair views that I had of one which was dying, looking down the back 
from the front of the head, not only was the gape of the lorica well seen to be but partial, 
but it evidently appeared that the cleft part was not elevated into a ridge, as it is in 
other species. The lorica-halves appear even to approach along the belly, as they do 
along the back. But I am not certain of this. Hach division terminates behind in 
an obtuse, slightly-decurved point (fig. 10), often obliterate. 
One individual of this species had two globose bladders protruding from the cloaca, 
as I have described in D. peta. It may indicate a prevalent form of disease in the 
genus. In one specimen was a large dark egg, nearly matured. Another had the 
alimentary canal greatly distended, and of a greyish-blue hue, an unusual colour in 
Rotifera ; but the mystery was explained by the fact that a colony of the Blue Stentor 
(S. ceruleus) was established on the same sprig of water-moss; and it became evident 
where the Diaschiza had obtained its dinner.—P.H.G.] 
Length. Total, ;3, to ,s inch. Habitat. Cheltenham; Woolston, numerous; 
Birmingham ; Stormont Loch, Scotland (P.H.G.): pools, rather common. 
1 This drawing was made from a protracted and excellent observation of a recently dead specimen, 
completed without any reference to my published figs. (Phil. Trans. 1886). Yet it is seen how exactly 
the details agree with those figs. (35-40), and especially with 39 and 40 of the Memoir. In examining 
many dead specimens of D. semiaperta, I have obtained accurately the appearance of fig. 37; the long 
produced, decurved points of the incus explaining what had seemed so inexplicable im situ. Iam, 
however, almost sure that these arching points proceed from the fulcrum between the rami, and are not 
prolongations of the wide glassy ramzt themselves. 
