76 Miscellaneous. 



A Sponge on Hyalonema. By Dr. J. E. Gkat, F.R.S. &c. 



Mr. Tennant kindly brought to the Museum a very fine thick spe- 

 cimen of the Japanese glassrope (Hyalonema) with a small quantity 

 of bark on it, and a triangular fan-shaped specimen of a true fibrous 

 sponge on the smaller end of it, which I considered a very in- 

 teresting specimen, as showing that a true fibrous sponge, as well 

 as the friable sponge forming the genus Carteria, was found para- 

 sitic on the apex of this sponge, 



Dr. Giinther, on looking at the specimen, was suspicious that the 

 sponge had been gummed on to the end of the glassrope ; but I 

 showed him that the fibres of the glassrope could be seen nearly to 

 the upper edge of the sponge. However, to make sure, we soaked 

 the sponge in the water ; and, lo ! the two sides of the fan-like body 

 separated, and showed that it had been cut down on one side, opened, 

 the ends of the fibres of the glassrope inserted, and the sponge then 

 glued together with gum on the edges and round the narrow base! 

 The sponge used for this purpose is the Spongia aculeata of Esper 

 (Zooph. t. vii. a), or a species very nearly allied to it. It is very 

 probable that more specimens of this kind have been prepared for 

 sale iu Europe. This is not like the square pieces of the bark of 

 Hyalonema, that were stuck on the ends of the fibres and figured as 

 isolated zoanthoid animals by Professor Wyville Thomson in his 

 account of this genus. 



It is a curious question if these artificial specimens are made by 

 the Japanese or by a French dealer in objects of natural history. In 

 both these cases the cement used is gum thickened with starch, just 

 such as is used by the French bird-stuffers for such purposes. 



On unequal Bivalve Shells. By Dr. J. E. Gray, F.R.S. &c. 



It has been generally believed, and I, think truly, that all equal- 

 valved shells live sunk perpendicularly in the sand, mud, or rocks, 

 attached by a byssus, which allows the water or food to enter on all 

 sides of them, and that the bivalves with unequal valves naturally 

 live lying horizontally on the surface of the rocks, or more or less 

 sunk in the sand, and that the inequality of the valves depends on 

 the permanence of this mode of life, and therefore is greatest in 

 such genera as Ostrea, which are fixed to rocks by the lower surface 

 of the under or attached valve. In some species of this genus, for 

 example, the upper valve is so small as to look almost like an oper- 

 culum. Unfortunately I have had little opportunity of verifying these 

 facts in the genera which have the valves only slightly unequal, as the 

 greater part of my time has been spent in the Museum, and the chief 

 part of my vacations in visiting and examining the various museums 

 of Europe. 



It would be very useful if persons living on the coast would verify 

 this theory, more especially as some genera (like Pandora) which 

 have very unequal valves are said to live free. 



My attention has been called to this fact by observing that Professor 



