2o8 

 THE SECTION PLACOSTYLUS OF THE GENUS BULIMUS. 



By EDWARD COLLIER. 



(Read before the Society, May 14, 1902). 



As the shells of the section Placostylus are our principal exhibit 

 to-night, I have been asked to give you some information about them, 

 as some years ago I worked up this group, liaving received a fine series 

 of these shells from the late Mr. E. L. Layard, of Budleigh Salterton, 

 S. Devon, who was for some time British Consul in the Fiji Islands, 

 and afterwards in New Caledonia. 



Their head-quarters seem to be New Caledonia and the adjacent 

 islands, but they are also found, though differing considerably in form, 

 as far north as the Solomon Islands, as far east as the Fiji Islands, and 

 in the south, two species are found in the North Island of New Zealand, 

 one in Lord Howe Island, and one in Rabbit Island, a small rock 

 close to Lord Howe Island. 



In Pfeiffer's 'Monograph of Bulinins'' only the following seven 

 species of Placostylus are described and figured, viz. : — 



1. Placostylus fih'atus Martyn. 



2. „ porphyrostomus Pfr. 



3. „ bovimis Brug. [shojign Lesson). 



4. ,, fjiligiiieus Pfr. 



5. „ salomonis Pfr. 



6. ,, cleryi Petit. 



7. ,, miltocheilus Reeve. 



But in Clessin's Edition, 1881, there are mentioned fifty-eight species 

 of Placostylus, including ten species of subsection Charis. In Paetel's 

 Edition, 1S90, there are, including Charis, which he raises to a section 

 by itself, seventy-five species and fifteen named varieties. 



The last work consulted and considerably used in writing this paper 

 is Martini and Chemnitz's "Conchylien-Cabinet" (1890-91), in which 

 they describe and figure no less than eighty-six species and fifteen 

 named varieties, although I believe they have omitted a few species. 

 I leave you to judge after seeing the large series of shells exhibited 

 to-night whether you do not think many of the so-called species are 

 only different forms caused by locality and environment. 



The shells of the section Placostylus are long conical shells, generally 

 wholly without umbilicus, many very strong and heavy, mostly coarsely 

 striated, or indented as if hammered, more seldom smooth and glossy. 

 The number of whorls vary between 4^ and 8, they increase regularly 

 and are separated by an appressed, generally slightly raised suture, 

 and mostly slightly notched. The upper whorls are mostly always 



