532 J. Slarkie Gardner — Eocene Aporrhdidce. 



most empbasized. The gi'eat distinction, however, lies in the form 

 of the wing, which is like the last, but a little more expanded, with, 

 a more pronounced upper digit, and also carried upward along the 

 spire to the fourth whorl, where it is truncated and expanded out- 

 wards into a quadrate projection of a flag-like form, at an angle of 

 about 60° to the axis of the spire. This flag is continuous with 

 the wing, projects some 12 or 15 mm., and has no supporting keel. 



It has been found at Hia:ha;ate and other localities round North 

 London and at Sheppey, and seems to replace A. Soiverbii, Mant., 

 in the London Basin, the latter having been perhaps more littoral iu 

 its habit. 



Aporrhais Margerini, De Koninck, 1837. Oldhaven Beds. 

 Plate XVII. Figs. 7, 8. 



This is by far the largest British species, measuring 50 mm. in 

 length, and 40 in breadth. The spire is blunt and composed of 

 7 tumid whorls, each about twice as wide as high. The ribs are 

 fine, except on the last w^iorl, not very prominent, and forming on 

 the body-whorl an upper row of strongly-marked rounded nodes, 

 a middle nodose keel, and a lower less-defined and almost simple 

 keel. The strias are faintly marked or absent. Each row of nodes 

 or nodose keel on the body-whorl is continued into the wing, the 

 upper forming a curved and not very pronounced digit, and the others 

 ending in slighter projections. The canal is short and curved in 

 the direction of the wing. The wing has, roughly speaking, the 

 outline of a shoulder-of-mutton, and is attached to either one or two 

 whorls above the body-whorl ; it is immoderately thickened, up to 

 7 mm. and slightly sinuous. 



All the specimens were obtained close together, between tide 

 marks at Heme Bay, west of Oldhaven Gap. The species as here 

 defined is new to the British Eocenes and seems rare or very local. 

 It is almost indistinguishable from the forms found in the ArgiJle 

 Bupelien de JBazele — a bed of Oligocene age. 



Aporrhais triangulata, sp. nov. Oldhaven Beds. Plate XVII. 



Figs. 3 and 4. 



This species differs from the last chiefly in its smaller size, the 

 largest measuring but 16 mm. in length by 15 across the wing. 

 It is a reduced almost facsimile of the last, except that the strise are 

 more distinct and the third or inferior keel on the body-whorl is less 

 pronounced. It is rather more obtuse and relatively shorter, and 

 the wing more triangular or shoulder-of-mutton-shaped than in A. 

 Sowerhii, which it agrees best with in size. 



This is very abundant at Heme Bay in the same beds, though not 

 actually associated with the last. 



Aporrhais Bowerbankii, Morris, sp. 1852. Thanet Beds. 

 Plate XVII. Figs. 9 and 10. 



The length of this species is 36 mm. and the breadth across the 

 wing 25. The spire is very elongated, regular, composed of 8 or 

 9 rather tumid whorls, higher than wide in the proportion of 9 to 5. 



