324 H. JAMES-CLARK ON THE AFFINITIES OF SPONGES. 



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 with Rhizopods; and I will therefore only state here my firm 

 conviction that the true, ciliated Spongm are not RMzopoda in any sense whatever, nor even 

 closely related to them, but are genuine, compound, flagellate. Protozoa; and are 'most inti- 

 mately allied to such genera as Manas (§§ 1, 2), Bicosceca (§§ 3, 4), Codonceca (§ 5), Codosiga 

 (§ 6), and Salpingaca (§§ 7, 8, 9). What are the special relationships of the numerous genera 

 of Sponges, I am not prepared to say; yet in regard to Leucosolenia botrgoides, there can be 

 no doubt that it is very closely allied to Codosiga and Salpingceca, but to which one more than 

 to the other would be difficult to determine. Codosiga (§ 6) is a compound form like Leuco- 

 solenia, and its individuals are united by a common, branching support, which has been 

 shown, by the changes which it passed through during fissigemmation, to be as fully alive 

 as the glairy, spicule-secreting cytoblastema of the Sponge. Salpingceca (§§ 7, 8, 9), on the 

 other hand, is a single monad, but excretes around it an envelope, or calyx, into which the 

 body is sunken in the same way that the monads (fig. 41, md) of the Sponge are imbedded 

 in the surface of their common dormitory. Inasmuch, however, as the calyx is probably an 

 excretion rather than a secretion, and appears as inanimate as that of Cothurnia, Vaginicola 

 and other Vorticelhdcs, it is more comparable to the spiculce (sp) than to the cgtoblastema of 

 Sponges. If one may draw an inference from the above considerations, it does not seem 

 at all improbable that hereafter we shall find that the monads of the different genera of 

 Sponges resemble the various genera of single and branching Flagellata, and then we will 

 be able to divide the former into such family groups as Momdoidce, Bicoscecoida, Codosigoidce, 

 Anthophgsoidce, &c. &c. 



Leucosolenia botryoides, Bowerbank, occurs on our sea-shore among the groups of Dgnamena 

 Sertularia, &c, and may be readily recognized by its ivory-white color. The colony is an 

 elongate mass, and seldom exceeds more than an inch or an inch and a half in leno-th and 

 resembles an irregular group of slender, contorted spines or forked horns (fio- 40) which 

 vary in thickness from one thirtieth to one sixteenth of an inch in diameter. At the' tip of 

 each horn is an aperture - the so-called excurrent orifice -large enough to be seen by the 

 unassisted eye. The whole mass is so transparent that not only the currents in the interior 

 but even the vibrating flagella and the pulsation of the contractile vesicles may be seen 

 with a strong light. The exterior consists of an excessively hyaline, cytoblastematous layer, 

 with scarcely, if any trace of organization of a cell-like character in it. Within this layer or 

 immediately beneath it, but certainly not in the monacligerous stratum, the faint yellow 

 spicula (fig. 64, sp, sp 1 ) are imbedded in systematic order, and overlap each other irregularly 

 in two or three layers. They present two diverse forms, namely, a simple aciculate° shape 

 (sp), and a stellato-tri-radiate (sp) one. The rays of the latter are slender, taperino- fre- 

 quently to a bifid termination, divergent at equal angles from each other, and lie in the 

 same plane. Without exception they are all arranged with one ray - often longer than 

 the others — projecting backwards, i. e, away from the excurrent orifice, and the other two 

 extending symmetrically right and left, and obliquely transverse to the longer axis of the 

 branch. In this manner they are disposed in a sort of net-work over the whole colony, even 

 close up to the excurrent orifices; and as the aciculate spicula lie parallel with the rays of 

 the other kind, there are consequently no projecting spines specially devoted to guarding the 

 entrance to these apertures. 



