imperfectly -defined Species of Jurassic Nautili. 287 



The largest specimen known to ns is from the Inferior 

 Oolite of Sherborne, Dorsetshire; its greatest diameter is 

 8 inches and greatest width 6^ inches. Distinct traces of the 

 anterior border of the muscular impression are observable on 

 the cast of its body-chamber. 



Horizon. Inferior Oolite. 



Localities. Bradford - Abbas, Sherborne, Dorsetshire ; 

 Bristol, Somersetshire. 



15. Nautilus Smitlri, sp. nov. 

 Fio-. 16. 



Nautilus Smith?.. — a, lateral view ; I>, front view, showing the ornaments 

 of the young shell and also the position of the siphuncle. Drawn 

 from a specimen in the British Museum (no. C. 747). About two 

 thirds natural size. 



Sp. char. Shell inflated, rapidly increasing, slightly com- 

 pressed on the sides, broadly rounded on the periphery. 

 Whorls much wider than high, widest in the region of the 

 umbilicus. The latter is small, with a subangular margin 

 and steeply sloping sides. • The septa are rather distant from 

 each other on the periphery, being half an inch apart where 

 the height of the whorl is If inch. The sutures are but 

 slightly curved on the sides and form a very shallow sinus on 

 the periphery. The siphuncle is slightly above the centre. 

 The test is ornamented with fine lines of growth, which tend 

 to gather into obscure folds and form a deep sinus on the 

 periphery ; these are crossed by close-set longitudinal lines, 

 more distinct in the young shell. 



Remarks. The chief distinguishing character of this species 



