PLATE XLII. 



PAGE 



Fig. 1. Polymastia agglutinans, vertical section, showing the arrangement of the 

 skeleton ; a, cortical layer of spicules ; b, grains of sand ; c, main 

 skeleton fibres ; cZ, small, scattered spicules ; x 45, . . . 213 



Fig. 2. Polymastia agglutinans, large stylus from the hody of the sponge; x 120, 213 

 Figs. •2a, 2b. Small tylostyli, found scattered in the soft tissues ; x 284. 



Fig. 3. Polymastia agglutinans, transverse section of one of the long, mammi- 

 form projections, showing the arrangement of t]\e skeleton ; a, cortical 

 layer of spicules ; b, subjacent layer of spicules ; c, longitudinal bands 

 of spiculo-fibre, seen in section ; d, zone of small spicules scattered 

 around e, the large central canal ; x 40, . . . . 213 



Fig. 4. Polymastia corticata, vertical section, showing the arrangement of the 

 skeleton; a, brushes of spicules in the outermost layer of the 

 cortex ; b, large, longitudinally placed spicules in the lower laver of the 

 cortex; c, choanosome ; x 45, . . . . 212 



Fig. 5. Polymastia coj-ticata, large stylus ; x 66, . . . .212 



Fig. 5a. Tylostylus from outermost layer of cortex ; x 284. 



Figs. 5b, 5c. Bases of two spicules from the inner layer of the cortex ; x 284. 



Fig. 6. Proteleia sollasi, vertical section of body, showing the arrangement of the 

 skeleton ; a, primary fibres ; b, outermost layer of cortical spicules ; c, 

 subjacent layer of cortical spicules ; d, grapnel spicules ; e, accumula- 

 tion of foreign matter on the surface ; /, choanosome, with scattered 

 spicules; x 44, . . . . . . _ 215 



Fig. 7. Proteleia sollasi, transverse section of one of the mammiform processes, 

 showing the arrangement of the skeleton; a, longitudinal bands of 

 spiculo-fibre, seen in section ; b, outermost layer of cortical spicules ; c, 

 ■subjacent layer of cortical spicules; x 12, . . . .215 



Fig. 8. Proteleia sollasi, large stylus ; x 120, . . . . .216 



Fig. 8a. Smaller stylus ; x 190. 



Fig. 8&. Grapnel .spicule ; x 190. 



Fig. 8c. Grapnel spicule, with terminal expansion but no teeth ; x 190. 



Fig. 8d. Free end of grapnel spicule ; x .900. 



Figs. 8e, 8/. Large tylostyli ; x 190. 



Figs. Sjr, 87/. Small tylcstyli; x 190. 



