Mr. H. J. Carter on the Freshwater Sponges of Bombay. 99 



EXPLANATION OF PLATES III. IV. and V. 

 Plate III. 



Fig. 1. Section of Spongilla Meyeni, natural size. 



a. Small spiculum and seed-like body of the same, magnified. 

 Fig. 2. Section of Spongilla plumosa, natural size. 



b. Small spiculum and seed-like body of the same, magnified. 

 Fig. 3. Section of Spongilla friabilis 1 natural size. 



c. Small spiculum and seed-like body of the same, magnified. 

 Fig. 4. Section of Spongilla alba, natural size. 



d. Small spiculum and seed-like body of the same, magnified. 

 Fig. 5. Section of Spongilla cinerea, natural size. 



e. Small spiculum and seed-like body of the same, magnified. 



As none of these species possess specific forms, it has been deemed advi- 

 sable to give sections of them, showing their average and relative thicknesses, 

 the form of the projections from their surface, and the peculiarity of their 

 internal structures respectively. 



Fig. 6. Magnified section of a seed-like body of Spongilla Meyeni, showing, 

 /, spicular crust ; g, coriaceous capsule ; h, internal cells, and i, in- 

 fundibular opening. 



a. Germs of cells magnified, — the largest g-^nr tn P art °f a » inch in 



diameter. 



b. Cell of seed-like body containing germs, magnified. 



c. Portion of coriaceous membrane magnified to show hexagonal divi- 



sions and transparent centres. 



d. Small spiculum of Spongilla Meyeni, magnified. 



e. One of its toothed disks with central aperture, magnified. 



Plate IV. 



Fig. 1. Disk to show the appearance which is presented on the surface of 

 the watch-glass a few days after the matter of the seed-like body 

 has been forcibly expelled into it under distilled water. 



a. Denticulated proteus in progression, showing its granules and hya- 



line vesicles, magnified. 



b. Passive state of the same, magnified. 



c, c, c. Germs parcelled out in semi-transparent mucilage, magnified. 

 d. Denticulated proteus, magnified. 

 e, e. Diffluent proteus, ditto. 



/. Vermiform proteus, ditto. 

 g, g. Animalcules about To7nj tn P art °f an mcn m diameter, which, to the 

 almost complete exclusion of all other kinds, were generally pre- 

 sent with the proteans, magnified. 

 h, h, h. Threads of semi-transparent mucilage, ditto. 



Fig. 2. A magnified view of a newly-formed portion of Spongilla, grown in 

 distilled water from a seed-like body, as seen with Ross's micro- 

 scope, under a compound power of £th of an inch focus. 



a. Sponge-cell with its granules and hyaline vesicles magnified, taken 



from the same portion. 



b. The same in a passive state, magnified. 



c, c, c. Marginal or thinnest portion of newly-formed Spongilla, ditto. 



d, d. Form of its extreme edge, ditto. 



e, e. Hyaline contracting vesicles, ditto. 

 /, /. Sponge-cells in situ, ditto. 



Fig. 3. Magnified view of a denticulated proteus with a portion of a spicu- 

 lum in a fold of its cell-wall. 

 Fig. 4. Ditto, with a loricated animalcule and germ in ditto. 



7* 



