Mr. H. J. Carter on the Spongozoon. 47 



cilium, transformed into psevidopodial prolongations, or, as 

 Prof. James-Clark has stated, " retracted " altogether. 



In 1871 (Annals, /. c. pi. 1. figs. 15, 16, &c.) 1 not only con- 

 firmed Prof. James-Clark's observations respecting the exist- 

 ence of the " collar," but fomid that in the spongozoon of 

 Grantia compressa it was supported on a neck-like projection, 

 to which I gave the name of " rostrum." Moreover it was 

 also proved, by the use of indigo-solution, that the spongozoa 

 of this sponge took in crude particles of this substance, while 

 similar monociliated bodies similarly grouped were also ob- 

 served in the marine siliceous sponges ; to which I can add 

 one of the horny species par excellence^ viz. an Aplysina 

 (Nardo & Schmidt), now belonging to the British Museum, 

 but which Mr. Kent lately found while dredging for sponges 

 on board the yacht ' Noma,' in Vigo Bay. 



Thus having found spongozoa in all the three divisions of 

 the Spongiadee, viz. in the Keratospongias, the Siliceospongige, 

 and the Calcispongi^, similar in form and similarly grouped, 

 we may reasonably infer that the spongozoon exists as such, 

 perhaps more or less modified, throughout the whole of the 

 Spongiadee, and therefore is the animal which constructs the 

 sponges generally. 



In Silliman's Journal for Dec. 1871 (reprinted in Annals, 

 vol. ix. p. 71, pi. 11) Prof. James-Clark confirms, so far as his 

 observations go, the principal points of my description and 

 figures of the " Ultimate Structure of Spongilla^'' given in the 

 ' Annals ' of 1857 (?. c), to which I have alluded in the first 

 part of this communication. 



But at p. 76 (Annals, I. c.) , where Prof. James-Clark states 

 that the groups of " monad cephalids " (our spongozoa) are 

 " not cells ; they are the heads of a polycephalic individual, 

 and consequently correspond functionally to the tentaculated 

 heads of polypi," I cannot agree with him, inasmuch as 

 they appear to me to be much more analogous to the groups 

 of Ascidians in the gelatinous structure of a Compound Tuni- 

 cated animal, where the little colony is divided up into 

 groups, furnished respectively with a common cloacal orifice 

 (Annals, vol. viii. pi. 2. fig. 41). Here I might add that some 

 of Schmidt's Halisarcinaj are so like the Compound Tunicata, 

 that his If. guttula appears to me to be one of the latter, and 

 no sponge at all. I speak, of course, from the actual exami- 

 nation of his specimen in spirit at the British Museum in 

 connexion with his published description. 



Further, Prof. James-Clark does not admit the existence of 

 a distinct cell round the groups of spongozoa, as I originally 

 described and fio'ured them as a whole under the name of 



