BY R. VON LENDENFELD, PH.D. 1147 



Fig. 4. — Ascetta procumbens. R. v. L. An adult spicule. The rays are conic 

 and rounded. In other species they do not have this shape. 

 F. Oc. II. 



Fig. 5. — Ascetta procumbens. R. v. L. A young spicule. The rays of which 

 are already so thick as those of the adult, only much shorter. 

 F. Oc. II. 



Fig. 6. — Ascetta procumbens. R. v. L. Schematic view of the interior 

 of the gastral cavity showing the reticulation of the ridges. 



Fig. 7. — Ascetta Maclaeyi. R. v. L. Painted from life. AA. Oc. II. 



Fig. 8. — Ascetta Macleayi, R. v. L. Transverse section through the upper 

 part of a colony. Osmicacid, AlumnCarmin, AA. Oc. II. The 

 black dots represent the flagellate cells. In this portion the Sponge 

 represents a tube of large diameter, a pseudosculum in the wall 

 of which small lacunes Ascon individuals or ciliated chambers 

 make their appearance. 



Fig. 9. — Ascetta Macleayi. R. v. L. Transverse section through a colony in 

 its thickest part. Osmic acid, Alumn Carmin, AA. Oc. II. The 

 dots represent the flagellate cells. The Ascon tubes in this 

 region of the Sponge are not connected by a membrane as 

 above. 



Fig. 10. — Ascetta Macleayi. R. v. L. Transverse section through the solid 

 peduncle. Osmic acid, Alumn Carmin, AA. Oc. I. 



Figs. 8, 9 and 10 are selected from a continuous series of sections made 

 through one specimen. 



Fig. 11. — Ascetta Macleayi. R. v. L. Longitudinal section through the 

 colony. Osmic acid, AA. Oc. I. The Pseudosculum (0) is formed 

 by asimple membrane above. Further down Ascon tubes are 

 found around it. The tube terminates as such below, just above 

 the middle of the Sponge. The central and lower part form a 

 free reticulation (s) here the Ascon-persons are not connected by 

 a membrane. (See fig. 9.) Towards the peduncle the Ascon 

 tubes become larger. The solid peduncle {p) extends below to 

 form a disc, by means of which it is attached. 



Fig. 12. — Ascetta Macleayi. R. v. L. Transverse section through a tube. 

 Osmic acid, Alumn Carmin, F. Oc. II. This section is near the top 

 of the Sponge, where the Ascon tubes are joined by a membrane 



