Aug. ], 1870.] 



HARDWICKE'S SCIENCE-GOSSIP. 



173 



with and strengthening the keratose skeleton : an 

 enlarged figure of the spicules is also given (fig. 161). 

 After stormy weather it is not uncommon to find 



160. Section of Chalina oculata. 



numerous specimens at almost any point on our 

 coast, but generally much beaten about, bleached, 

 and denuded of the external membrane. 



Fig. 161. Spicules of Chalina oculata. 



Another sponge less common, smaller, firmer, and 

 more compact in its habit, is that next figured 

 (fig. 162), called Halichondria ramosa. It is by no 

 means our intention to enter here upon the descrip- 

 tion of the characters of the genera, or why one 

 should be a Chalina and the other a Halichondria, 

 which would extend this chapter beyond reasonable 

 limits. We would only observe that in Chalina 

 there is a fibrous skeleton of keratose, and that in 

 Halichondria the spicules are cemented together 

 into a network. The specimen figured is called 

 Dictyocylindrus ramosus by Dr. Bowerbank. When 

 alive, this sponge is yellow, orange, flesh- colour, 

 pink, or crimson ; acquiring a brownish colour in 



the dry state. The height seldom exceeds three 

 inches, and there is very considerable variation in 

 the ramification. The branches are frequently much 



Fig 1 . 162. Htilichondria ramosa. 



compressed. Near Torquay specimens have been 

 dredged as much as ten inches high. This sponge 

 when dried presents a very marked difference from 

 the Chalina, in that the spicules project all over the 

 surface, so as to give the sponge a hairy -like appear- 

 ance. The spicules are of a similar character, but 

 differ in size from those of the Chalina, and there 

 are none in the membrane. In neither case are the 

 spicules attractive as microscopic objects. 



Fig. 163. Halichondria panicca. 



The last sponge to which we purpose alluding is 

 quite as common as the first, and more so than the 

 last. It has been called the " crumb-of-bread " 

 sponge [Halichondria panicea), from its resem- 

 blance when dry to a piece of the crumb of 

 white bread. When alive it ranges from light 

 ash to yellow, orange, or green. The shape varies 

 exceedingly, sometimes enveloping the stems of the 



