26 Mr. H. J. Carter on 8])onges. 



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. 



Fig. 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 ; g, sponge-cell with rostrum, collar, and 

 cilium retracted, and pseudopodia alone put forth. 



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

 degrees of protrusion {b), and the collar only seen in a a. 



Fig. 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 compressa. Sponge-cell with collar transformed into 

 tentacular pseudopodia, one of which bears a monad on its 

 point, a. 



Fig. 18. The same, sponge-ceU vrith monociliated cell (a) 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. 



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

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

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

 the arrows, h. 



Fig. 21. The same, sponge-cell {a) similarly attached to a group. 



Fig. 22. The same, collar transformed into pseudopodia, cilium remaining. 



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

 formed into pseudopodia, cilium remaining. 



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

 cilium wholly, transformed into pseudopodia. 



Fig. 25. Grantia compressa. Sponge-cell with rostrum, coUar, and cilium ; 

 presenting pseudopodia at the fimdus of the cell. 



Fig. 26. Clathrina sulphurea, sponge-ceU of; rostrum and collar retracted, 

 and cilium also becoming retracted by thickening at the base. 



Fig. 27. Grantia ciliata. Sponge-ceU with rostrum, collar, and cilium ; 

 the collar very faint. 



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

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

 faint. 



Fig. 29. Grantia compressa. Group of sponge-ceUs which had assumed 

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

 the interior. Common. 



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

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

 cilium in motion. 



Fig. 31, The same, specimen of the same after the sponge had been im- 

 mersed in spirit and water. 



Fig. 32. Grantia ciliata. Quadriradiate spicule, magnified, on the scale 

 of l-24th to l-6000th 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 ; 

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

 canal (this is the common form of tJie ^nradiate in this sponge 



