18 Prof. H. James-Clark on the Animality of the Ciliate Sponges. 



tion here, because it forms a collateral link with Codosiga in the 

 affiliation of the Sponges with the Monadina. This genus I 

 have called Salpingceca. It is, as it were, a single individual of 

 Codosiga, which does not possess a stem, but is seated in a calyx^ 

 from which it protrudes, or into which it retracts, at will. There 

 are three well marked species, of which one is marine. 



I now come to the principal object of this communication. 

 The sponge which formed the maiir basis of these investigations 

 is the well-known marine species, Leucosolenia [Grantia) hotry- 

 oides, Bowerbank. It is preeminently a branching form, and, 

 on account of the slenderness and transparency of its tapering, 

 hollow ramules, is a most desirable object for study. A branch- 

 let, and, in fact, the whole colony, may be stated to be essen- 

 tially a double tube. The outer tube consists of a glairy, gela- 

 tiniform stratum in which the spicules are imbedded in a certain 

 order, and is pierced by numerous ostioles, which are continued 

 through the interior tube to its hollow centre. The inner layer 

 or tube is entirely made up of the individual members of the 

 colony, the bodies of which are packed together closely, side by 

 side, like pavement-stones, with their posterior ends slightly 

 imbedded in the glairy substance of the outer tube, and their 

 anterior ends projecting freely into the general cavity. To de- 

 scribe the shape and organization of one of these individuals 

 would be to repeat, almost word for word, what I have already 

 said of the monad of Codosiga ; in short, Leucosolenia bears some 

 such sort of relationship to Codosiga as Salpingoeca does, the 

 latter being, as it were, a stemless Codosiga seated in a calyx, 

 whilst Leucosolenia is comparable to a stratum of the monads 

 of Codosiga imbedded in a spiculiferous envelope. It is clear 

 therefore that the organic difference between Leucosolenia and 

 Codosiga is scarcely enough to locate them in two different fami- 

 lies ; in fact, I am inclined to regard them as only generically 

 distinct, and hardly, if at all, more widely separated in this re- 

 spect than are Salpingoeca and Codosiga. 



What are the diversities of other genera of the Spongi^ 

 ciLiATiE I cannot more than conjecture ; but seeing that one of 

 the genera is so closely related to the monociliate flagellata, 

 it can hardly be possible that the others are very far removed ; 

 and I shall feel warranted, therefore, in assuming, upon the 

 premises, that the whole group of SpoNGiiE ciliate is as inti- 

 mately allied with the monociliate Infusoria flagellata as it 

 is possible for it to be without actually constituting with the 

 latter a uniform family. 



