AKD PHYSIOLOGY OF THE SPONGIAD^. 
823 
PLATE XXVIII. 
Fig. 1. Regular arenated keratose fibre from the skeleton of a coarse rigid Australian 
sponge, x90 linear: page 757. 
Fig. 2. Regular arenated keratose fibre from a flexible sponge, one of the common 
Bahama sponges of commerce, xl75 linear: page 757. 
Figs. 3, 4, and 5. Portions of skeleton-fibre from a specimen of Dysidea fragilis, 
JoHNSTOX, illustrating the varieties of form of irregular arenated keratose 
fibre, Xl08 linear: page 757. 
Fig. 5. Showing the mode by which the apex of the fibre attaches itself to a single 
grain of sand, X 108 linear : page 757. 
Fig. 6. Smooth solid siliceous fibre, with young fibres pullulating from the adult ones at a. 
From the skeleton of M^Andrewsia azoica^ Geay, x 175 linear: page 758. 
Fig. 7. Tuberculated solid siliceous fibre from the skeleton of Dactylocalyx jpumicea, 
Stutchbuet, x 108 linear: page 758. 
Fig. 8. Tuberculated solid siliceous fibre, very prominently tuberculated, from Dactylo- 
calyx Prattii, Boweebank, ms., x 175 linear: page 758. 
Fig. 9. Fibrillated sponge-fibre from the skeleton of one of the sponges of commerce, 
X 308 linear : page 754. 
Fig. 10. Fibrillated sponge-fibre from the skeleton of an Australian sponge, X 175 linear: 
page 754. 
Fig. 11. Spinulated simple fistulose siliceous fibre, from a sponge in the collection of 
Dr. Aethue Faeee, Farrea, Boweebank, MS., Xl08 linear: page 758. 
Fig. 12. Cidarate prehensile fibre from a parasitical siliceo-fibrous sponge from the 
South Sea, showing the position of the prehensile organs at the base of the 
sponge, x83 linear: page 759. 
Fig. 13. A group of cells on a portion of the interstitial membrane of Ecioncmia acervus, 
Boweebank, MS., x666 linear: page 759. 
Fig. 14. Cells on a portion of the interstitial membrane of HalicJiondria nigricans^ 
Boweebank, MS., x308 linear: page 759. 
Fig. 15. Detached nucleated cells from a new species of sponge from Freemantle, 
Western Australia, X 308 linear: page 759. 
Fig. 16. A view of the upper stratum of cells of one of the ovaria of Spongilla friaMlis^ 
Caetee, X 308 linear: page 760. 
PLATE XXIX. 
Fig. 1. A piece of an interstitial membrane from the honeycomb sponge of commerce 
in the condition in which it came from the sea, exhibiting the sarcode on its 
surface, and the imbedded semi-digested minute molecules, x666 linear: 
page 760. 
