a new Genus and Species of Sponges. 195 



diagram, situated on canal-loops which have thus two open- 

 ings in connexion with an excretoiy duct, future discovery 

 must determine. 



It is useless to attempt this in a sponge which has been pre- 

 served in spirit, or in any other way after death ; for the sarcode 

 is too delicate to retain the form of its minuter parts unaided 

 by vitality. Hence it is necessary to pursue these researches 

 with the sponge in the living condition, and under experiments 

 perhaps similar to those instituted by myself in the examina- 

 tion of Spongilla, whose ultimate structure, so far as I have 

 gone, never could have been obtained under any other circum- 

 stances. In the present instance, however, Ave may consider 

 ourselves fortunate in having met with a species in which the 

 continuity of the pore or cup-like body and the excretory 

 canal can be clearly demonstrated even after preservation. 



Another question, which can only be determined during life, 

 is the form and nature of the sponge-cell engaged in the nutri- 

 tive function. 



In Prof. James-Clark's valuable paper (Memoirs of the 

 Boston Society of Nat. History, read June 20, 1866, and re- 

 printed in the 'Annals,' 1868, ser. 4. vol. i.), it is naturally 

 urged that, because the ciliated cells of the calcareous sponge 

 called Leucosolenia hotryoides have a funnel-shaped process 

 round their cilium, and particles drawn by the cilium into 

 the funnel pass thence into the body, they are taken into 

 the latter through a fixed oral aperture, close to which also 

 the undigested portions make their exit, as in his genus 

 Codosiga &c., among the flagellated Infusoria. Further, 

 Prof. James-Clark thinks it not improbable that such might 

 be the case with the ciliated cells of Spongilla possessing the 

 ear-like appendages which I have figured in the ' Annals ' 

 (ser. 3. vol. iii. pi. 1. figs. 12, 13, 14), these being, in his opi- 

 nion, merely the sides in profile of the funnel-shaped process 

 not otherwise seen — an appearance which he himself has re- 

 cognized. But it may be observed that, among the sponge- 

 cells of the " ampullaceous sac " of Spongilla [1. c), there were 

 not only monociliated but also unciliated sponge-cells which 

 had equally incepted the particles of carmine. It is possible 

 that the funnel-shaped process and the cilium may have been 

 retracted here, in accordance with Prof. James-Clark's obser- 

 vations of the latter in Codosiga (p. 193, 1, c.) and of the former 

 in Leucosolem'a (footnote, p. 208, tb.) ; and this might be his 

 explanation of their absence, the oral orifice remaining fixed 

 and stationary as before. Still such retraction Avould not be 

 less characteristic of the Rhizopoda than of the Infusoria 

 flagellata. 



