LAVARD : MIMICRY IN MOLLUSCA. 387 



Solomon Isles, with its deep orange mouth. My son, who 

 collected for me in these islands, tells me it is found on broad- 

 leaved plants, on the leaves, and that the animal shines through 

 the shell, a lovely green, and the orange mouth barely shows 

 from the upper side, so that the shell is most difficult to find, 

 approximating so closely to the green leaves on which it creeps. 

 -Surely these two cases are instances of protective mimicry ? 



Further on, Mr. Mason alludes to the destruction of the 

 epidermis in some shells ' by the action of the winds and the 

 sharp angles of the drifting sands.' This reminds me of the 

 action of sand (and heat) in New Caledonia, where I resided 

 some seventeen years, on the magnificent Bjtlinii {Phuosfyli) 

 found there. They are essentially forest shells, always found 

 under trees, but one or two species — Pi. porphyi'ostoiniis and 

 PL inouackensis for instance — are found in the low scrub of the 

 sea littoral. Now, those found in the forests, where the large- 

 leaved trees afford plentiful shade, have — even in the most 

 adult examples — a lovely brown epidermis on the upper part, 

 though the lower is almost always worn away down to the 

 'calcareous matter of the shell, by crawling on the rocks and 

 stones. Those that live in the sandy littoral of the sea shore, 

 where the scrub is open and the small-leaved trees give little 

 shade, are invariably, when fully adult, deprived of their epider- 

 mis, while in youth they always possess it. They all burrow 

 down into the soil, and I doubt not the ' sharp angles ' of the 

 hot sand (so hot that you can sometimes hardly bear to lay 

 your hand on it) do a great deal to grind off their epidermis. 

 There is a fine species from the Solomon Islands — PL cleryi — 

 of which I am informed that not one in five hundred adults 

 has the epidermis (I have a fine example), while the young have 

 a lovely greenish one. I should like to know the life history of 

 this species, where it is found, etc. 



At page 338, our President mentioned the case ' where the 

 normally coloured opaque bands become translucent.' I have 

 some lovely examples oi Heli:x; Jioiiensis of this nature, taken by 



