224 



externally by numerous longitudinal ribs, chambers 



formed by transverse septa perforated by a tube 



which is either central or marginal. 



O. LEGUMEN. Lam. 6. F. p. 237. NAUTILUS L. 

 JWfi..ll64. D.p. 350. Gualt. t. 19./. P.Turt. 

 D.p. 121. (TFatt. t. 3. / 74. N)Mont. Sup. p. 

 82. t. 19. / 6. Lin. T. 8 p. 118. White, smooth, 

 glossy, transparent, somewhat flattened, a little concave 

 on one side, \vithout marginal ridge on either side, a 

 little curved, slightly tapering or nearly of equal diam- 

 eter at both ends, the extremes a little rounded and 

 contracted ; joints eight or nine, divided by oblique 

 lines, the anterior or larger end oblique and margined, 

 with an obtuse syphon which rises above the margin and 

 a considerable aperture near the concave side. Variety, 

 N. RECTUS. Mont. p. 197. t. 19. /. ,l.Turt.V. 

 p. 121. Walk.f. 74. Straight and subcylindrical. 

 Variety, N. SUBARCUATUS. Mont. p. 198. t. 6./. 

 5. Turt. D. p. 122. The three anterior chambers 

 more globose than the rest. 0,12 Margate, fyc., in fine 

 sand. 



O. COSTATA. F. p. 236. NAUTILUS C Mont. p. 

 199. t. 14. /. 5. D. p. 348. Turt. D. p. 122 

 Lin. T. S.p. 120. Straight, subcylindrical, with from 

 five to twelve raised articulations which are adorned 



