26 Mr. H. J. Carter on Sponges. 



appears to have become transformed into the rostrum ; g, conical 

 form of the same, where the rostrum presents a pointed elonga- 

 tion in the centre, with flat top ; A, similar form, showing the 

 contracting vesicle, i. 



Fiy. 14. The same, group of sponge-cells, part of which show the rostrum 

 in different degrees of protrusion, apparently without the collar, 

 but with the cilium ; y, sponge-cell with rostrum, collar, and 

 cilium retracted, and pseudopodia alone put forth. 



Fig. 15. The same, group of sponge-ceUs showing the rostrum in different 

 degrees of protrusion (6), and the collar only seen in a a. 



Fiy. 16. The same, five sponge-cells, of which three present the collar &c., 

 and the other two (a) the pseudopodia only. 



Plate II, 



Fig. 17. Grantia cnmjn-essa. Sponge-ceU with collar transformed into 

 tentacular pseudopodia, one of which bears a monad on its 

 point, a. 



Fig. 18. The same, sponge-cell with monocOiated cell (o) seized by the 

 margin of the collar. 



Fig. 19. The same, group of sponge-cells with collar and cilium respec- 

 tively, which appear to have undergone duplicative division, on 

 stolons of sarcode. 



Fiy. 20. The same, sponge-cell with a single pseudopodium extended 

 laterally from the fundus and attached to the glass (a), round 

 which it was propelled by the cUiimi in a circle represented by 

 the arrows, b. 



Fiy. 21. The same, sponge-cell (a) similarly attached to a group. 



Fiy. 22. The same, collar transformed into pseudopodia, cUiimi remaining. 



jF^^. 23. Clathrina sulphurea, sponge-cell of; rostrum and collar trans- 

 fonned into pseudopodia, cilium remaining. 



Fig. 24. Leuconia nivea, sponge-cell of; rostrum partly, and coUar and 

 cilium wholly, transformed into pseudopodia. 



F^g. 25. Grantia cn/npressa. Sponge-cell with rostrum, collar, and cilium ; 

 presenting pseudopodia at the fundus of the cell. 



Fig. 26. Clathrina sulpJiuria, sponge-cell of; rostrum and coUar retracted, 

 and cilium also becoming retracted by thickening at the base. 



Fig. 27. Grantia ci/iata. Sponge-cell with rostnmi, collar, and cilium ; 

 the collar very faint. 



Fig. 28. Leuconia nivea. Sponge-ceU with rostrum, collar, and cilium ; 

 the rostrum beaded upon its anterior edge, and the collar very 

 faint. 



Fiy. 29. Grantia conipresxa. Group of sponge-cells which had assumed 

 a round or elliptical form, with their cilia rapidly vibrating in 

 the interior. Common. 



Fiy. 30. The same, two living sponge-cells after their bodies had become 

 more or less filled witli indigo, presenting rostrum, collar, and 

 cilium in motion. 



Fiy. 31. The same, specinu^n of the same after the sponge had been im- 

 mersed in spirit and water. 



Fig. 32, Grantia ci/iata. (^Juadri radiate spicxile, magnifled, on the scale 

 of l-24th to 1-OOOOth of an inch, common to the internal sur- 

 face of the cloaca in most of the calcareous sponges ; showing : — 

 a a, the two arms, which are generally more or less curved ; 

 b, the straight arm, which generally presents a trace of axial 

 canal (tiiis is the common form of the /n'radiate in this sponge 



