rORIFERA [sponges]. 



31 



Carnosa or Fleshy Sponges. 



The sponges of this small group either have no hard skeleton at Case IV. 3. 

 all {Ohondrosia), or merely scattered stellate spicules {Chondrilla). 

 They possess a well-marked rind inclosing a softer " pith," and the 

 canal system is highly developed. 



ChondroHla reniformis, or the Sea-Kidney (Case IV. 3), has a 



Fig. 14. 



Section of Gendia showing crust of globular spicules, radiating bundles of 

 tridents and needles, and small stur-shaped flesh spicules. Magnified 50 

 diameters. (After Bowerbank.) 



smooth rounded surface, on which one or two small circular oscules 

 are present ; the numerous pores are not visible to the naked eye. 

 The sponge, being devoid of a hard skeleton, shrinks greatly when 

 dried, but swells up again on being immersed in fluid. Apart from 

 the absence of trident spicules and of a hard skeleton, the Carnosa 

 show many affinities with the Four-Ray Sponges. 



