HALF AN HOUR WITH SPONGES. 59 



specific name, is a dirty white. The thickness of 

 the sponge is only about a quarter of an inch, but 

 its summits are raised to about three quarters of an 

 inch, and rounded off. Its colour, and crisp and 

 gritty feel, will at once serve to identify it. In the 

 three-rayed form of its spicules, it appears to be 

 related to the Grantia. 



A more attractive object than those just men- 

 tioned is the Hymeniaeidon caruncula, a red-lead, or 

 orange-coloured sponge, about an inch in diameter, 

 having ridges about a quarter of an inch high. 

 Each of the little ridges or peaks is perforated as 

 usual. There is very little appearance of " sponge- 

 flesh " on this species, so that it may readily be 

 distinguished from another belonging to the same 

 genus, called albescens. The former has spicules 

 pointed only at one end, whilst in the latter they are 

 pointed at both ends. The latter is distributed over 

 the rock in winding worm-like masses, of an orange- 

 yellow or buff colour, and having a characteristic 

 " spongy " feel. Moreover, it throws up a series of 

 processes or filaments, some of which are an inch 

 in length. The most abundant of all these rock- 

 encrusting sponges, however, is Microciona carnosa. 

 It is a well marked species, and one easily to be 

 identified. Our readers will see the impossibility of 

 our doing other than give verbal descriptions of these 

 kinds of sponges, as none but coloured illustrations 

 would otherwise give any idea of them. The colour of 

 the species we are now dwelling upon is a pale Indian 



