COLLIER : THE SECTION I'LACOSTVLUS OK THE GENUS HULIMUS. 2I3 



wlien adult, as they rub off the epidermis by burrowing in tlie hot 

 sand, where they hve near the seashore. I show you a specimen of an 

 adult P. porpliyrostomus completely decorticated, and an immature 

 one showing the epidermis in beautiful condition. In other species 

 which live in the damp forests, the epidermis seems to dry and peel off 

 even in the cabinet, as you will see by the specimen I exhibit of P. 

 insignis. 



Mr. Layard's son was collecting B. miltocheiliis in the Solomon 

 Islands, and found it most difficult to see them on the leaves of the 

 trees, as the animal is green and shows through the shell — a very 

 good example of protective colouring. 



The New Hebrides have not yet been fully worked for shells, as the 

 natives are very savage and great cannibals. Only two species of 

 Placostylus and two of Charts have so far been found, and these only 

 in the southern part of the group. A new genus (^Diploniorpha of 

 Ancey) seems to take their place in the other islands of the group, 

 specimens of which are exhibited to-night, as the Manchester Museum 

 secured Mr. Layard's duplicates. The type of the genus is Diplo- 

 morpha layardi Brazier. There have so far only been four species of 

 this genus discovered, and of one of them there is only one specimen 

 known. One of the species is named after Monsieur de Latour, vi^ho 

 with his son was collecting for Mr. Layard, and who were both mur- 

 dered by the natives, and few Europeans have landed on the island 

 since. The gentleman who collected and sent him the other died 

 there of fever — not a very pleasant prospect to go collecting in a 

 country like this. 



Diploinorpha is closely allied to Pa/tula, but the tooth and twist 

 in the outer lip make them look like a diminutive Placostylus, and 

 all the more so as they are terrestrial, whilst the Partula are arboreal. 

 They undoubtedly are a link to the Placostylus. 



And now, in conclusion, I wish to point out to you that as neither 

 Australia nor New Guinea have any Placostylus, we may conclude that 

 they have been separated from New Caledonia from a very remote 

 period, as on the map you will see that down the coast of Australia 

 there seems to be very deep water (2,600 fathoms), another fact point- 

 ing to there having been no connection between these lands in recent 

 times. 



The theory of a continent stretching across the Pacific to South 

 America, I think we may dismiss at once, as the shells only seem 

 somewhat similar in form, and these only to the species from locali- 

 ties furthest away from South America. As to all this Placostylus 

 region having been one continent, I think that the shells hardly sup- 

 port the theory, as they differ so much amongst themselves in form 

 and character. 



