AND PHTSIOLO&Y OF THE SPONGIAD^. 
829 
Fig. 11. A fragment of a similar ovarium to that represented by fig. 10, the fracture 
shovring its extremely thin condition, X 308 linear : page 815. 
Fig. 12. A young ovarium of the same species as that represented by fig. 10, in an early 
stage of development, X 308 linear : page 815. 
Fig. 13. A reticulated ovarium in situ, on the fragment of a sponge from Madeira, 
X 108 linear : page 816. 
Fig. 14. A portion of the reticulated structure from an ovarium of the same description 
as represented by fig. 13, X 308 linear : page 816. 
Fig. 15. An ovum in course of development into a young sponge on the same membrane 
as that on which the ovarium represented by fig. 13 is seated, X 108 linear : 
page 816. 
Fig. 16. A group of ova or gemmules in course of development into young sponges, 
found, with many others, on the inner surface of a fragment of a large Pecten 
from Shetland, X 108 linear : page 817. 
Fig. 17. A small portion of the skeleton of Iphiteon j^anicea in the Museum of the 
Jardin des Plantes, Paris, with gemmules in situ, X 183 {Pactylocalyx, 
Stutchbuet) : page 817. 
Fig. 18. A gemmule detached from Iphiteon ^anicea, X 666 linear: page 817. 
Fig. 19. A gemmule extruded from near the base of a specimen of Tetliea Lyncurium, 
on the distal extremity of one of the skeleton fasciculi, X 50 linear : 
page 819, 
PLATE XXXV. 
Fig. 1. A group of internal gemmules in situ, on the interstitial membranes of Tetliea 
cranium : — a, one of the larger and most completely organized gemmules ; 
h, h, h, three of the smaller and more simple gemmules which always accompany 
the larger ones. In Canada balsam, X 108 linear : page 818. 
Fig. 2. One of the larger description of gemmules of Tetliea cranium, in its natural 
state, removed from the membrane and viewed by direct light, X 25 linear: 
page 818. 
Fig. 3 represents a portion of the sponge from the East Indies, furnished with numerous 
depressed porous areas with protecting organs, natural size : page 794. 
Fig. 4. Two of the inhalant areas, connected by the dermal network : — a, the external 
protective organ in a perfect condition ; h, having the external protective organ 
removed to exhibit the deeply depressed porous area, X 50 linear: page 794. 
Fig. 5. Half of one of the external defensive organs, highly magnified, to exhibit the 
disposition of the spicula on the follicular radiations of the organ, X 108 
linear: page 794. 
Fig. 6. A view of the interior surface of half of one of the external defensive organs, 
exhibiting the structure of the semifollicular radiations of the organ, X 108 
linear: page 794. 
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