SALPINADA. 85 
much exceeded by the stout straight and long alvines. For many years I knew it only 
by a single dead specimen found in a pool at Maidenhead in September 1851. But 
recently (March, 1885) I met with a healthy example on Myriophyllwm in one of my re- 
servoirs at Torquay, which enabled me to complete my diagnosis and delineation. 
The great head is sub-lobate, beset with brushes of cilia, stout in the middle, becom- 
ing more slender on all sides. A great occipital brain carries a very large and brilliant 
red eye, and a rounded antennal lobe, bearing a few sete. The great mastax, when 
feeding, is protruded through the mental smus. The abdominal viscera are normal, 
except that the gastric glands seem wanting; and there appear to be two contractile 
vesicles, into which the two lateral canals open by a trumpet-shaped mouth. 
The manners were similar to those of other Salpine, nibbling eagerly and persever- 
ingly, as it crept, the vegetable surface of the milfoil, with its protruded trophi. 
After it had remained in energy for several hours, I killed it, by mingling with the 
water in the live-box a minute drop of sol. caust. pot., whereby all the soft parts were 
instantly dissolved. There remained, however, uninjured, 1, the great red eye, which, 
in one aspect, had a quadrate form: 2, the two toes: 8, the whole manducatory 
apparatus. A few minute air-bubbles were scattered through the visceral cavity. I 
could now discern that the surface of the lorica is not at all scabrous, by which (as well 
as by the other peculiarities already adduced) it may well be distinguished from Ehren- 
berg’s S. ventralis, to which it yet approximates.—P.H.G.] 
Length. Of lorica, ,, inch; breadth and depth, each 53,; length of toes, 35. 
Habitat. Maidenhead; Torquay (P.H.G.). 
S. EUSTALA, Gosse, sp. nov. 
(Pl. XXII. fig. 5.) 
[SP. CH. Occipital spines wanting ; pectoral pair short, incuwrved ; lumbar spine 
conical, short, arched ; alvine pair very long, stowt, and incurved ; dorsal cleft narrow, 
of equal width. 
The lorica is gracefully ventricose, the back and sides being much arched, the belly 
slightly. The great alvine spines strike attention, as a conspicuous feature in all aspects ; 
they being long, thick at their bases, and incurved to the points, which are obtuse and 
approach each other. The lumbar spine is the united termination of the two dorsal 
ridges; it is only half the length of the alvines, conical and sharp-pointed, slightly 
arched on the dorsal edge. The dorsal cleft, narrow and of equal width throughout, 
reaches to the very front edge, which then is nearly horizontal on each side, but on 
reaching the pectoral side, after a deep sinus, rises to a short sharp spme. The whole 
surface of the lorica, ventral as well as dorsal, appears stippled or punctured with 
minute sunken dots. But, in some examples, this is hardly perceptible; while, in 
others, it is coarse and conspicuous. The head, viewed laterally, is about as deep as 
the body; the front is made up of an intricate series of eminences (carefully delineated 
in fig. 5a); one large lobe, toward the mentum, is crowned with stout and long cilia, 
which curve forward uniformly when in vigorous motion; other lobes carry much finer, 
shorter, and straighter cilia. There is a thick, obtuse, antennal lobe, bearing a brush 
of fine sete near, but not at, its extremity ; and, within its walls, are seen curves and 
lines connected interiorly with a great descending brain, near the point of which is a 
round red eye. The internal structure is, in general, normal. But what appears peculiar 
is that there are (if I have not greatly erred) two coequal and consimilar contractile 
bladders symmetrically placed, large and conspicuous, each of which receives the dilated 
end of a lateral vessel.! And this does not seem to be a series of twisted cords, but a 
long slender sac, dilated here and there, where globular vacuoles are seen within. 
' These vesicles were exactly alike, each subtrigonal, seated (optically) on each side of the circular 
orifice for the outlet of the foot. Each was evidently the terminus of the respiratory apparatus of its 
side, which, a rather wide ribbon or bag of clear tissue, containing several vacuoles, opens by a trumpet. 
