244 J. 8. Gardner — British Eocene Land Mollusca. 



are filled witli infiltrated granular limestone and arragonite, witbont 

 betraying any outline of their former living occupant. Their asso- 

 ciation in such abundance with land-shells, and especially with the 

 young of Bulirmis, suggests that they may not improbably have been 

 the eggs of the latter. Many Bulimi lay eggs of even larger size ; 

 but the only examples in the British Museum are eggs of species 

 with relatively very large body-whorls, I have so far not been able 

 to obtain information as to the form of egg laid by the living species 

 of the AmpMdromus section of the genus. The eggs, if such, are 

 certainly very large in proportion to even the fullest grown adult ; 

 but they might have passed, for the internal mould of the body- 

 whorl is 19 millim. across, and the eggs at their greatest diameter 

 but 15 or 16 externally. The recent eggs of the large Bulimi, where 

 there is ample space in the body-whorl, are regularly oval ; but in 

 these fossils the sides are perfectly straight, and this peculiarity 

 rather favours the assumption that they may really be the eggs of 

 the cylindrical-shelled Bulimus, especially as none of the fry of this 

 species are ever found of smaller diameter than the supposed eggs. 

 The size of the egg in living Fulmonates bears no settled relation to 

 the size of the shell. The texture of the shell is rugged, but in all 

 the recent eggs I have seen it is smooth. The question cannot, how- 

 ever, be definitely settled until further observations are made. 



Internal moulds of Bulimus were formerly found abundantly 

 in the Bembridge Limestone at Sconce. Fine specimens with the 

 shell replaced by carbonate of lime were always rare and of some 

 value,^ being among the handsomest of our many fine Eocene mol- 

 lusca. Though the horizon of the species is the Bembridge Lime- 

 stone, it must have existed throughout the whole of our sub-tropical 

 Eocene period, for part of a shell from the London Clay is figured 

 by Mr. Edwards, and he has specimens from the Middle Headon of 

 Brockenhurst and Hordwell, as well as the Upper Headon of Headon 

 Hill. The National Collection is very rich, comprising at least a 

 dozen fine specimens of the adult shell. 



The species appears to be extinct, but one very closely allied, B. 

 chloris, Eeeve,is a native of the Philippines, and there are many others, 

 as B. perversus, of the same group inhabiting the same region. B. 

 chloris is a bright yellow shell, somewhat smaller than ours, but so 

 closely resembling it in all other respects, that we are fully justified, 

 in believing that ours is an ancestral form, or genetically connected. 

 Sandberger compares it with B. palaceus, v. d. Busch, and B. Winteri, 

 Pf., from Java. No species resembling it occurs in other regions, and 

 the group, which is very distinct, is, as already stated, separated 

 under the sub-generic name AmpMdromus. 



BuLTMUs (Amphidromus) l^volongus, Boubee, 1844. PL VL Fig. 1. 



Bull. Soc. Geol. i. ser. 1, p. 213, M. de Serres, Ann. des Sciences Nat. 1844, p. 180, 



pi. xii. fig. 9. 

 Sandberger, die Susswasser-Conchyl. 1870-75, p. 287, pi. xvi. fig. 7. 



The introduction of the present species into our Eocene fauna is 

 ^ 20s. seems to have been an established price. 



