292 PYRAMIDELLID^. 



smooth within, at first but slightly convex, subsequently 

 avcuatcd at its junction with the pillar-lip. This last, 

 which usually recedes far below the level of the opposite 

 lip, is narrow, thin, and elongated, occupying nearly two- 

 thirds of the length of the aperture ; it is straightish 

 above, obliquely curved below, and not reflected in the 

 most perfect example we have seen, but in some broken- 

 mouthed individuals it appears in the shape of an appressed 

 lamina. There is rarely the least vestige of a fold, but 

 when present it is very oblique, retired, and rudimentary. 

 The axis is imperforated. The breadth of the shell is only 

 a line ; its length is occasionally the fifth of an inch. 



Very few examples have been taken of this extremely 

 scarce species. Mr. Alder obtained his specimens at 

 Tynemouth ; Mr. Hanley dredged a single dead one at 

 Herm, near Guernsey, in seven or eight fathoms depth ; 

 and Mr. Clark from deep water in the offing at Exmouth. 



0. Wakkenii, Thompson. 



Base with spiral striulre, elsewhere smooth. Spire not much 

 elongaterl. Mouth rather long : no fold on the pillar. 



Plate XCVl. fig. 2, 3. 



Rissoa Warrenii, Thompson, Ann. Nat. Hist. vol. xv. p. 315, pi. 19, f. 4. 



TurhonUla ohliqiui, LoviiN, Index Moll. Scandin. p. 19 ? 



Odostnmia „ .rEFFREVS, Ann. Nat. Hist, new scr. vol. ii. p. 341. 



„ dcvorata (not of Zeitschr. Malak.), Jeffrkvs, Ann. Nat. Hist. IB.'iO, 

 p. 109. 



A comparison of the types or originally described ex- 

 amples of the decorata and Warrenii has fully convinced 

 us of their identity. The specific characteristics are more 

 strongly developed in the innuature dead specimens, which 

 form the decorata of cabinets, than in the Hue living indivi- 



