NEWTON AND HARRIS: BRITISH EOCENE CEPHALOPODA. 127 



This species differs from iV". centralis in that the siphuncle is 

 not central, whilst the extremities of the dorsal lobes are broad 

 and reflected. The shell is orbicular ; septa lunate. Some authors 

 have regarded N. Lamarcki, Desh., as synonymous with this, but 

 we find that Sowerby's species is much more inflated and orbicular. 

 Common. 



Formatmis and Localities. — Bracklesham Beds : Bracklesham Bay. 

 London Clay : Whetstone, Hampstead, near Chalk Farm, Woking, 

 Sydenham, near Kew Bridge, Primrose Hill, Highgate Archway, 

 Sheppey, Potter's Bar, Odiham, Norwood Tunnel, and Brentford. 



Natjtilus eegalis, J. Sowerby. 



Nautilus regalis, J. Sby. (?). — Mineral Conchology, 1822, vol. iv. 

 p. 77, pi. ccclv. J. de C. Sby. — Min. Con. 1843, vol. vii. 

 p. 35, pi. Dcxxvii. fig. 5. Edw.— Mon. Pal. Soc. 1849, 

 p. 46, pi. iv. ; pi. viii. fig. 5. J. de C. Sby. — Dixon's 

 "Sussex," 1850, pp. 121, 228. Foord.— Cat. Poss. Ceph. 

 British Museum, 1891, pt. 2, p. 318. R. B. Newton.— 

 Syst. List Edwards Coll. British Museum, 1891, p. 290. 



Shell smooth, flattened on the sides, and roughly rounded ; dorsal 

 lobes short, rounded, deeply concave, and not reflected ; siphuncle 

 small and excentric. Easily distinguishable from the two preceding 

 species by its umbilicus, which is closed by a thickening of the lip, so 

 that the shell appears to have a solid axis. Its form is less ventricose 

 than that of N. centralis. 



Formation. — London Clay. Localities. — Chalk Parm, near Copen- 

 hagen House, Whetstone, Coast of Essex, Hornsey, Sheppey, near 

 Chalk Parm, Potter's Bar, St. Katharine's Docks, Hyde Park, Boreham 

 Wood, and Copenhagen Fields. 



Nautilus Sowerbyi, J. de C. Sowerby. 



Nautilus, n.sp., Wetherell. — Lond. & Edinburgh Phil. Mag. 1836, 



vol. ix. p. 466. 

 Nautilus Sowerhyi, J. de C. Sby. — Mineral Conchology, 1843, vol. vii. 



p. 35, pi. Dcxxvii. figs. 1-3. Edw. — Mon. Pal. Soc. 



1849, pi. vi. p. 48, pi. viii. fig. 3. J. de C. Sby.— Dixon's 



"Sussex," 1850, pp. 121, 228, pi. xiv. fig. 15. Foord.— 



Cat. Foss. Ceph. British Museum, 1891, part 2, p. 323. 



R. B. Newton. — Syst. List Edwards Coll. British Museum, 



1891, p. 291. 



Shell smooth, discoidal, lenticular ; aperture triangular ; septa very 

 concave ; the lateral lobe causing a deep sinus-like depression on each 

 side, which is more developed than in N. urbanus, and slightly 

 approaching LLercoglossa Parkinsoni in this respect ; siphuncle near 

 the dorsal margin. Bather rare. 



Formation. — London Clay. Localities. — Bognor, Potter's Bar, 

 Whetstone, Finchley, Holloway, Chalk Farm, Highgate, Sheppey, and 

 Portsmouth (?). 



VOL. I. — JUNE, 1894. 9 



