NAUTILUS. 17 



ceding whorl ; margin of the septa flexuous ; siphuncle sub-central, but rather nearer to 

 the ventral than to the dorsal margin. 



Diameter 3J inches, breadth 2 inches. 



Found occasionally in the Chalk with siliceous grains, at Chardstock. ]\I. D'Orbigny 

 quotes it as common in beds of the same age in the North and West of France. 



Our specimens have a rounder back and more flexuous septa than M. D'Orbigny's 

 figure of N.Jleuriausianus, in which characters they approach his figure of N. Soioerhyanus, 

 from which they are distinguished by a smaller umbilicus. I am inclined to regard them 

 both as one species, and have adopted the name of N. fleuriausimim, as the other would 

 be liable to confusion with the N. Sowerbii of the ' Mineral Conchology.' I have only 

 seen casts of the N. fleuriamianm, which do not show the siphunculus, and have 

 described its position upon the authority of M. D'Orbigny's figure and description. 



11. Nautilus Fittoni, Sliarpe. Plate VI, fig. 4. 



Nautilus compeessus, Fitton. Trans. Geol. Soc, 2cl series, vol. iv, pp. 203 and 

 367, Note. 



N. testa lavi, compressd, complanatd, umbilicatd; laterihus planis, obliquis ; dorso 

 angusto, rotundato, i?i medio Ihieato ; umbilico magno ; aperturd truncato-sagittatd, apice 

 rotundatd ; siphunculo sub-ventrali ; septtorum marginibus Jlexuosissimis. 



Shell discoidal, smooth ; sides flat, sloping ; back narrow and rounded, marked with a 

 faint line along the middle ; umbihcus large, allowing the inner whorls to be seen, its 

 walls nearly perpendicular ; aperture sagittate with the angles rounded off"; septa with a 

 very flexuous margin ; siphuncle very near the lower margin of the whorls. 



Diameter about 3 inches, breadth I inch. 



This shell has a good deal of resemblance to N. Saosbii of Morris, in general form, 

 proportions, and flexure of the septa ; but difiers from that species in its rounded back. 



This species was first noticed by Dr. Fitton in the Upper Green Sand, Western Lines 

 Isle of Wight, and placed in the Museum of the Geological Society ; it is called in his lists 

 N. compressus, which name had unfortunately been previously apphed to another species. 

 It has since been found by Mr. Wiest in the Chalk with siliceous grains of Chardstock ; , 

 both of the specimens are imperfect. It is named after the original discoverer. 



Ammonites, Bruguiere. 



Animal unknown : shell chambered, discoidal, compressed or ventricose, spiral, with 

 contiguous whorls regularly convoluted on the same plane, the last partially or entirely 

 concealing the previous whorl : chambers separated by transverse flexuous septa, deeply 

 sinuated towards the edges, divided into branching lobes, and traversed by a continuous 

 tube situated at the outer or dorsal edge of the shell ; the last chamber large. 



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