104 DESCRIPTION OF SHELLS FOUND 



large ; spire extremely small ; aperture obliquely oblong ovate, 

 straitened above and expanded below ; outer lip thin, not continu- 

 ous ; destitute of an umbilicus. 



9. BULBUS SMITHII. N. S. — Smith. 

 Plate I. Fig. 18. 



Shell very thin, ventricose, subglobose, smooth, glossy, and desti- 

 tute of an umbilicus ; spire consisting of three obtuse, depressed vo- 

 lutions, which are separated by a deep groove ; aperture somewhat 

 semi-lunar or oblong-ovate, straitened and pointed above, and ex- 

 panding widely and rounded at its base ; outer lip thin ; pillar-lip 

 broadly reflected on the columella above, and narrowing as it de- 

 scends ; colour pale reddish-brown, and livid grey ; length an inch 

 and a quarter ; breadth an inch and a tenth. — B. 



Found at Ardincaple near Helensburgh, by Lady John Campbell. 



10. ARCA PAPILLOSA. N. S. — Smith. 

 Plate I. Fig. 19- 



Shell transversely elongated ; umbones prominent, placed nearest 

 one side and inflected ; apices separated by a broad flattened space, 

 which is obsoletely striated transversely ; a series of divergent papil- 

 lose ribs emanate at the beaks, and radiate towards the base and 

 sides of the shell ; these are crossed by several strong lines of 

 growth ; margins externally and internally crenated ; the centre of 

 the valves are slightly hollowed externally ; length three-eighths of 

 an inch ; breadth six-eighths. — B. 



Found at Port Rush by Mr Smith. 



11. CRASSINA MULTICOSTATA. N S. 

 Plate I. Fig. 20. 

 Shell suborbicular, strong, rather depressed, with numerous close- 

 set, concentric ribs, which become somewhat obsolete towards the 

 sides ; covered with a yellowisb-brown epidermis ; umbones pro- 

 minent, considerably turned to one side, beneath which is a lanceo- 

 late depression ; hinge with a strong triangular central tooth in the 

 right valve, with a slight pit on each side, for the reception of the 

 tooth of the opposite valve ; on the edge of that next the anterior 

 side is a thin lamellar, divergent tooth, with a very minute one in 

 the same situation on the opposite side, beyond which is a remote 

 lateral tooth ; in the left valve are two divergent central teeth, with 



