246 J. S. Gardner- — British Eocene Land MoUusca. 



specimens, not more than three or four will be found in an adult 

 state, with the lip of the shell reflected. 



I have not, as I have already mentioned, been able to come across 

 any specimens or account of the eggs of the group of Amphidromus. 

 The large eggs of the true Bulimus are of very firm consistence, and 

 translucent as alabaster. Eeeve describes a soft-shelled egg, like 

 that of a snake, as being deposited in little clusters on the trees, 

 between two leaves, which the animal curls up one on another as a 

 receptacle for their protection. Woodward mentions that one of the 

 largest species deposits its calcareous eggs among dead leaves. 



Fam. OLEACiNiDji;. 



Glandina costellata, Sowerby, sp. Plate VI. Fig. 2. 



Syn. Achatina costellata, Edwards, Eocene MoUusca, Order Pulmonata, p. 7o, 1852. 



The shell is cylindrical, fusiform, dextral, imperforate, composed 

 of 6 whorls ; the aperture narrow and elliptical. The ultimate 

 whorl or nucleus is obtuse, but the general form of the apex is acute. 

 The whorls forming the spire are wider than high, the 4th whorl in 

 the figured specimen measuring 5 mm. in height, with 8 mm. as the 

 diameter of the suture, and the 5th whorl 11 mm. in height, and 

 18 mm. for the suture. The whorls are irregularly convex, slightly 

 constricted in some individuals towards the sutures, which are well 

 defined. The length of the body-whorl is at least double that of the 

 spire, and exceeds it even four times in abbreviated examples. It is 

 much longer than wide — 44 to 25 mm. in the figured specimen — the 

 greatest convexity is central and parallel with the suture, and it 

 becomes attenuated towards the base. The test is thin ; marked 

 with irregular lines of growth, rarely coarsely ribbed, 3 ribs occupy- 

 ing 2 mm. ; or finely striated in the same direction, when there are 

 5 strige to a millimetre. Mr. Edwards thus describes the sculpturing : 

 " The edges are slightly pressed against the preceding volution, so 

 as to present a narrow band running round the spire, parallel with 

 the suture ; the ribs are rounded, irregular, rather oblique, and 

 slightly thickened above the sutural band, giving a rough crenulated 

 appearance to the edges of the volutions ; they are crossed saltier- 

 wise, by very faint obscure lines of growth, perceptible only in well- 

 preserved specimens." ^ The aperture is narrow, longitudinal, ellip- 

 tical, outer lip crescentic, inner pear-shaped, coming to an acute 

 point above, and more or less rounded below. The lips are thin and 

 sharp. The columella thin, rather bowed and truncated at the base ; 

 the latter character affording a basis of separation between this 

 genus and Achatina. The length of the shell appears to be 62, and 

 the diameter 25 ram., though these are not the extremes observed in 

 the largest individuals. 



The National Collection comprises upwards of 60 specimens, well 

 illustrating the great variability in the relative proportions of the 

 whorls and aperture in this species. The MS. name brevis attached 



1 Eocene Mollusca, p. 75. 



