J. Starkie Gardner — Eocene Aporrhdidce. 531 



tumid, mucb. wider thnn high, the proportion being as 6 to 3|-. 

 The spire is usually ribbed, the ribs extending right across from 

 suture to suture, more pronounced in the centre, slightly bowed 

 away from the wing, and so close together that one occurs within 

 every half millimetre on the last whorl of the spire (next the 

 body- whorl). The ribs are sometimes entirely absent, and occa- 

 sionally a varix is present. The spire is always regularly striated, 

 the stride being well deianed and at least 3 to the millimetre. The 

 body- whorl becomes slightly angulated as the wing is approached, 

 and the ribs betray a tendency to separate into two rows of 

 elongated nodes, which gradually coalesce into two ridges or keels 

 as they pass on to the wing. The upper keel is produced into a 

 digit directed upward at an angle of about 40° from the spire, the 

 lower one projects very slightly beyond the margin of the wing. 

 Its general contour is something like the wing of a bat ; and inclined 

 to be notched, or to have a sinus close to the canal, which is short. 

 The strise ai'e continued all over the upper surface of the wing, 

 fanning out, but without becoming more numerous. The wing is 

 sometimes attached to the body-whorl only, sometimes it extends 

 over three, but as a rule it is attached to two whorls. This description 

 only applies to the adult shell, the wing not commencing to be 

 developed until the spire is full-grown. After the wing attains 

 to its full spread, it receives repeated deposits of shell and becomes 

 much thickened. The aperture presents no important characters, but 

 the inner lijj is callus, though the callosity is not continued far over 

 the body- whorl. The outermost shelly layer of the spire sometimes 

 peels off in the fossil, carrying away the strise, and leaving the 

 ribs quite smooth and very distinct. 



About 8 shells in the Edwards' collection are separated as "variety 

 elongata,'' the spire being more regularly scalariform, with more 

 strongly-marked ribs. The retention of a separate name for so 

 unimportant a variation seems to me useless. This species abounds 

 at Clarendon, Bognor, Alum Bay, Aldboro, and Southampton, in 

 the Hampshire Eocene Basin, but is not found in the London Basin. 

 One specimen from Southampton is of rather larger size and slightly 

 bridges the distinction between that and the London Clay sj)ecies to 

 be next described. 



It is represented in Figs. 5 and 6 of Plate XVIL, the originals 

 being from Clarendon. 



Aporkhais labellata, sp. nov. London Clay. 



There are but few specimens of this species in the British 

 Museum, only two or three are perfect. 



The average length of the shell is 34 and the breadth 27 millims., 

 though one with a longer canal measures 40 mm. The spire is more 

 regularly tapering, formed of 8 or even 9 whorls, less tumid than in 

 the last species, and with the last but one, as well as the body-whorl, 

 slightly angulated. The ribs are coarser, one rib occupying 2 mm., 

 and rather more bent, and separating into two distinct series of 

 rounded nodes on the body- whorl, the upper of which is by far the 



