94 GENUS XIX, NAUTILUS. 



one chamber apparent and conical ; the former liaving 

 been successively effaced by the filling up of the parti- 

 tions (see Belemnites, Park, Organ. Rem, 3. p. 122, t. 8. 

 f 8 to 15), 



Di SCORE IS. A spiral discoidal univalve ; the turns all con- 

 tiguous, uncovered, and perceptible ; the septa trans- 

 verse, whole, and frequent (see Park. Organ, Rem, 3. 

 p, 159, t, 11, f, 1), 



RoTALiTEs. A convex, conical, spiral, multilocular, imivalve, 

 slightly radiated beneath ; the opening marginal, trigo- 

 nal, and rather turning downwards (see Park, Organ, 

 Rem, 3, p, 160, t. 11, f 2 and 3), 



Lenticul'na. a sublenticular, multilocular, spiral univalve; 

 the external margin of the turns being complicated, the 

 septa reaching to the centre on each side : the septa en- 

 tire, curved, and standing out, on the upper and under 

 surface, like rays ; the aperture narrow, and projecting 

 beyond the penultimate turn (see Park, Organ. Rem, 3, 

 p. 161. t. II. f 4). 



IjITUOlj. a multilocular univalve, partly spiral, the last turn 

 being straight at the end ; the chambers irregular ; plain 

 transverse septa, the last having several openings (see 

 Park. Organ. Rem. .3. p. 161. t. 11. f. 5 to 7). 



Spirolina. a multilocular shell, in part spirally convoluted ; 

 the turns contiguous, the latter ones straight ; the septa 

 transverse, and perforated by a tube (see Park. Organ. 

 Rem. 3. p. 161. t, 11, f S and 9), 



