406 Vl'ILSON. 



EXPLANATION OF PLATE XXV. 



(Fig. 5 original — the other figures borrowed to illustrate the section " Re- 

 marks on the Morphology of Sponges.") 



Fig. I. AnamLxilla torresi. Trans, section, from Polejaeff, Challenger Report 

 on Calcarea, PI. IV, Fig. 2a. 



Fig. 2. Leucilla connexiva. Trans, section, from Polejaeff, PI. VI, Fig. la. 



Fig. 3. Leucilla uter. Trans, section, from Polejaeff, PI. VI, Fig. 2a. 



Fig. 4. Leuconia multiformis. Trans, section, from Polejaeff, PI. VI, Fig. 3a. 



Fig. 5. Diagrammatic section of an hypothetical silicious sponge. 



Fig. 6. Leucandra caminus. From Vosmaer's Spongien, Taf. I, Fig. iS, after 

 Haeckel. 



Fig. 7. Plakina monolopha. Vertical section, from Schulze. Zeit. fiir Wiss. 

 Zool., 34. Bd., Taf. XX, Fig. 4. 



Fig. S. Young Plakina monolopha, just attached. Vertical section, from 

 Schulze, 1. c. 



Fig. 9. Plakina dilopha. Vertical section, from Schulze, 1. c. Taf. XX, 

 Fig. II. 



Fig. 10. Plakina trilopha. Vertical section, from Schulze, 1. c. Taf. XXI, 

 Fig. 12. 



Fig. II. Rhagon stage of Oscarella lobularis, after Heider, from Korschelt 

 und Heider's Lehrbuch, p. 6. 



Reference Letters to this Plate. 



In. can. Intercanal. 



