310 A MONOGRAPH OF THE AUSTRALIAN SPONGES, 



A MONOGRAPH OF THE AUSTRALIAN SPONGES. 



By Dr. R. von Lendexfeld. 



II. — Continued. 



MORPHOLOGY AND PHYSIOLOGY OF 

 THE SPONGES. 



I will endeavour to give a brief account of our present know- 

 ledge on the subject, without entering into detail, which will be 

 described below in the classificatory portion of this work. 



I. — The Anatomy of the Sponges. 



1. Shape and size. 



Although many Sponges have a constant shape, which is 

 characteristic for the species, still the greater number do not 

 possess a definite form. The same species will always be charac- 

 teristic in outer appearance, but a certain shape which could be 

 minutely described and set up for a standard is not met with in 

 most Sponges. Just as a tree although growing irregularly, will 

 have peculiar points about it, which give the character to the 

 landscape so it is with the Sponges. 



The irregular Sponges appear in every conceivable shape. 

 Those which have a constant shape are generally cylindrical, 

 always with a circular transverse section, which points to 

 the fact that we have here animals before us, which originally 

 irregular, are just commencing to attain a regular radially sym- 

 metrical shape, or vice versa. The latter appears more probable. 



