as Infusoria flagellata. | 205 
cles of considerable size were seen to make their exit at the 
base of the flagellum. No digestive vacuoles were noticed, 
although the body was often found filled with food. 
The contractile vesicles (cv) usually amount to three or four, 
and rarely to five in number ; or there are two very large ones, 
which occupy nearly the whole breadth of the body (fig. 37). 
They occur in all parts of the body except its neck, and beat 
with a sluggish systole about at the same rate as those of 
Codosiga (§ 6). 
_ The calyx (c, c!) has very much the same proportions as the 
body, over which it is fitted as if upon a mould. Its posterior 
half (c) is globular, and is attached at its hindermost, axial 
termination to the point of support. Although hundreds of 
specimens of this species were observed, not one of them had 
a pedicel. The anterior half tapers, like the thick neck of an 
urn, from the posterior one to one-third of its diameter, and then 
rapidly widens and terminates with a flaring, smooth-edged 
aperture (c!), which is about twice as wide as its narrowest 
segs The margin usually is exceeded by the projecting 
ead, so that the former may be seen quite readily as a distinct 
ring behind the circular edge of the front, from which the collar 
_ rises. The empty calycles (fig. 37°) were found very frequently, 
and so nearly identical in form with those of the living eds 
that they must have possessed considerable rigidity. That 
they are, however, to a certain extent flexible and plastic, was 
shown on one occasion, when the body and neck suddenly re- 
tracted and swelled laterally (fig. 374) to an extent which was 
considerably beyond the usual breadth of the calyx and its 
neck, and then returned to its former shape and proportions. 
§ 10. Leuwcosolenia (Grantia) botryoides, Bowerbank. 
Pl, VI. figs. 40-44; Pl. VII. fig. 64. 
If I were now to describe merely the congregated Monads 
of this compound animal without giving it a name, any one 
who had already become acquainted with the structure of Co- 
dosiga (§ 6) would set down the first as a colonial, massive 
form of the latter. In fact a glance at a figure of a free- 
swimming individual (fig. 23) of Codosiga in one of its nume- 
rous attitudes, and then a momentary inspection of the monad. 
(figs. 42,43, 44) of this Sponge would almost induce one to 
believe that the two belonged to the same genus, nay, even to 
the same species, as far as the representations referred to are 
concerned. 
In the introductory section of this memoir I have already 
discussed the theory of Carter as to the alliance of Sponges 
Ann. & Mag. N. Hist. Ser. 4. Vol. i. 15 
