as Infusoria flagellata. 20 5 



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 

 portion. The margin usually is exceeded by the projecting 

 head, 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 body 

 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. 37*^) 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. Leucosoleuia [Grantia) hotryoideSj Bowerbank. 

 PI. 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 



