142 A MONOGRAPH OF THE AUSTRALIAN SPONGES, 



IV. — FromT. E. Schultze to the present day, 1875 — 1884. 



Tn no branch of Biology has such an advance been made 

 within the last ten years as in Spongiology. 



The papers to be mentioned here shall be reviewed more briefly 

 than the preceding ones, because we shall have to repeat their 

 contents anon : we cannot write a history of a period which is not 

 completed. 



We shall have to divide the papers of this period into five 

 groups, and shall commence as in the foregoing chapter with the 

 Anatomy. 



Anatomy and Histology. 



In a series of papers (102) Schultze describes very accurately 

 many genera of sponges belonging to several different groups. 

 His results are in the main features the following : — The sponges 

 consist of three layers Ectoderm, Entoderm, and a third, which he 

 hesitatingly calls Mesoderm. 



The Ectoderm consists throughout of simple flat ciliated cells, 

 which cover the outer surface of the sponge, and the walls of the 

 canals through which the water flows from the outer surface to the 

 ciliated chambers. 



These ciliated chambers, together with the canals leading from 

 thence to the Oscular tube, and also this tube, are covered with 

 Entoderm al cells, which in the chambers of the ordinary, and in 

 the corresponding tubes of the calcareous sponges, have the shape 

 of long, fringed and ciliated elements, whilst in the canal system they 



(102). F. E. Schulze. Ueber den Ban und die Entwiclcelung der Spongien. 

 Zeitschrift fiir wissenschaftliche Zoologie. Sycandra ray nanus Supplement, 

 Band, XXXV., Seite, 247. Entwickelungsgeschichte von Sycandra. 

 Band, XX VII., Seite, 486. Die Gattung Halisarca, Band, XXVIII., Seite, 

 1. DieFamilie der Chondrosidse, Band, XXIX., Seite, 87- Die Familie der 

 Aplysinidse, Band, XXX., Seite, 379.' Metamorphose von Sycandra, Band, 

 XXXI., Seite, 262. Die Gattung Spongelia, Band, XXXII., Seite, 117. 

 Die Familie der Spongidse, Band, XXXII. , Seite, 593, Die Gattung 

 Hircinia Hand, XXXIII., Seite, 1. Die Plakiniden, Band, XXXIV., Seite, 

 407. Cortichvm candelabrum, Band, XXXV., Seite, 410. 



