236 



The Museum Gazette 



Lighthouse, which measured 7 ft. 4 ins. in circumference 

 and ift, gins, in depth. 



Fig. 4 is taken from Johnston's 69th plate, and represents 

 the burrowing sponge (Cliona celata, Grant). Oyster shells, 

 perforated by Cliona, are abundant on our coasts. The 

 burrow superficially resembles that of the Anobium beetle 

 in wood and furniture, but in section the galleries are exten- 

 sively lobed. In some cases the sponge bursts " through 

 the shell and forms large cork-like masses, the identity of 

 which with the boring portion was for a long time unsus- 

 pected." Specimens showing this condition may be seen 

 in the British Museum. Similar ones would no doubt reward 

 the diligent observer in many localities on our coasts. The 

 boring sponges and the huge Neptune's cup sponges (Poterion 

 patera) — a fine specimen may be seen in the Haslemere 

 Museum — together belong to the order Monaxonida or 

 Monaxon sponges characterised by the pin-shaped skeleton- 

 spicules. The Cliona bores into limestone rocks as well as 

 shells. 



Professor Martin Duncan writes " The substance of 

 this sponge, which is called Cliona (Kleio, to shut), consists 

 of soft, granular, greenish-yellow protoplasm, no harder than 

 setting strong gum and water, and it completely fills up 

 the cavities in which it lives. It is traversed and covered 

 with myriads of spiculae, which are slender cylindrical tubes, 

 slightly curved, acutely pointed at one end, and terminated 

 by a small, hollow, round head at the other. The spiculse 

 of the Cliona are of flint, and are transparent, and they are 

 not placed in contact with any muscular fibres, nor is the 

 sponge stuff sufficiently dense to afford them a support 

 against even slight pressure. It is necessary to mention 

 this, because some people believe that the sponge works 

 its spiculae in such a manner as to drill the holes and 

 tubes in which it is found. The oyster (shell) is hard, and 



The Sea-shore," S.P.C.K., 1891, p. 78. 



