NOTOMMATAD A. 49 
brain has a turbid yellowish appearance, at times clearly defined. The alimentary canal 
is very large, darkly granulate, composed of many sacs ; and a slender rectum clearly 
opens into a cloaca below the tubercular tail. Convoluted lateral canals run down each 
side; but no contractile vesicle could be discerned. 
The manners are sluggish ; it twists and wriggles much, with little change of place. 
It is a fine large species, not devoid of elegance when extended; but it often contracts 
into very uncouth shapes.—P.H.G.] 
Length, ;; inch. Habitat. Maidenhead; an aquarium at Torquay (P.H.G.): rare. 
D, GIBBER, Gossc, sp. nov. 
(Pl. XIX. fig. 7.) 
[SP. CH. Body encased in a transparent leathery sheath, hunch-backed ; face 
prone ; frontal proboscis small ; toes long, decurved. 
In sediment from one of my window-reservoirs, I found this large Diglena. About 
the size of D. grandis, 11 much resembles that fine species in general appearance. Its 
form is that of a cylinder, flattened along the belly ; the entire soft parts are encased in 
what we might call a lorica, only that it is manifestly flexible: a difference, perhaps, 
merely in degree. This sheath, of a glassy transparency, is almost unchangeable in 
shape; yet it has marked creases here and there, which are permanent, serving for 
needful flexibility. At what might be called the shoulders, it rises to a conspicuous 
conical hump, diminishing thence by a gradual slope to the hinder parts. The internal 
organs do not rise above the cylindrical body-wall, leaving thus an ample cavity within 
the sheath all down the back; quite empty, save that a very delicate conglobate gland, 
attached by a thread to the hinder extremity, works up and down within it, by the con- 
tractions and contortions of the animal. What seemed the trochal front was, through 
the inclination of the head, nearly on the level of, and continuous with, the ventral sur- 
face, and was covered with vibratile cilia. Behind, the body-sheath is cut off obliquely, 
with a well-marked edge, for the emission of a stout foot, which carries two long curved 
blade-like toes, often thrown widely apart. On each toe, at about one-fourth of its 
length, there is an abrupt decrease of diameter on its superior edge, with the appearance 
of a jomt; and a delicate line crosses each near its point. 
This individual appears to have been subjected to the remarkable accident of the 
protrusion of the entire mastax, with all its accessories, from the frontal face, so that it 
was totally unable to retract it. Whether this was the result of over-eagerness in feed- 
ing, producing unguarded muscular exertion, or of violence from some of its predatory 
foes, I cannot guess. I could discern no mark of any pinch on the body. But there 
was a great extruded mass of flesh, amorphous and motionless, yet bearing a manifest 
resemblance in outline to a mastax: while in an occasional glance that I could get at 
its front, I saw what looked exceedingly like a long ineus and a hooked malleus on each 
side, though only the bottoms of these organs could be shaped, and that very vaguely. 
Besides, there was not a trace of mastax to be seen within the head, for I searched 
carefully for it; the protruded mass was just where it would be, if such a misfortune 
had occurred; there was a conspicuous constriction behind the mass, evidently pre- 
venting retraction; while the mass was apparently of definite and unyielding shape, 
containing hard and lengthened organs. ‘The frontal disk, both above the mass and 
also to a small extent below it, was covered with cilia in rapid, but feeble vibration ; 
no whorls were produced in the surrounding floccose ; no swimming or crawling pro- 
gress was made by the animal; though it constantly contorted its body, and threw about 
its toes. Its vital power was manifestly stricken, and even the movements gradually 
grew feebler and feebler. I had not detected the slightest motion within the (supposed) 
mastax ; its nerves had been probably paralysed at once. But fragments of the floecose 
sediment kept on adhering to the exposed parts, as if these were glutinous; and this 
was more manifest at first than after some time. From the summit of the front a 
minute finger-like proboscis descends. —P.H.G.] 
VOL. II. E 
