OP CONCHOLOGY. 101 



OBSERVATIONS ON RECENT AND FOSSIL SHELLS, 

 WITH PROPOSED NEW GENERA AND SPECIES. 



BY T. A. CONRAD. 



CEPHALOPODA. 

 NAUTILID^E. 



NAUTILUS, Breyn. 



Nautilus perforatus, Conrad. — Journal of the Academy of 

 Natural Sciences, second series, vol i., p. 213. 



As it is impossible to say whether Solander's scrohiculatus 

 represents this species or umbilicatus, I retain the name under 

 which I described it. Chemnitz's figure, if intended for this 

 shell, is badly drawn, as the umbilicus is represented as much 

 wider, the volutions narrower, and the aperture with wider 

 outer margin and direct sides, whilst in the present shell the 

 sides slightly taper, and the outer margin is much more acutely 

 rounded. 



Dillwyn says the volutions of scrohiculatus are smooth, but 

 in our shell the whorls are transversely striate and undulato- 

 plicate. The centre of the umbilicus is perforated, and there 

 are minute close rugose lines on the back, which are well 

 represented in Knorr's figure, vol. iv., t. 22, and which figure 

 agrees very well with N. perforatus in every detail except 

 color. Under the lens the flat sides exhibit minute rugose 

 and granulated transverse lines, but no longitudinal ones, 

 which are limited to the rounded dorsal region. 



HERCOGLOSSA, Conrad. 



Nautiloid ; septa angular and linguiform ; apex of the angle, 

 or tongue-shaped lobe, not contiguous with the adjacent sep- 

 tum ; siphon large or moderate, situated within the centre, 

 or between the middle and inner margin, and not dorsal or 

 funnel shaped, but tubular and gradually tapering. 



NAUTILUS ORBICULATUS, Tuomey. 



This genus contains Aturia Matihewsoni, Grabb, and perhaps 

 another from N. Jersey. Eocene species, Nautilus Parkinsoni, 

 Edwards. An undoubted species of Aturia, which is charac- 



