130 



NAUTILUS cariniferus. 



TAB. CCCCLXXXIL— /g^. 3 and 4. 



Spec. Char. Discoid, subglobose ; inner whorls 

 half exposed in a large umbilicus ; a keel in 

 the middle of each side, and two ridges be- 

 tween it and the flattened front. 



In general form this resemblesNautilus biangulatus (tab. 

 4i58,Jig. 2.) ; but in addition to the angles which charac- 

 terize that, it has on each side of a broad flat front two 

 ridges or lesser keels ; in this it approaches N. multica- 

 rinatus, but that has a narrow concave area in place of the 

 principal keel upon the side. The lesser keels in N. ca- 

 riniferus disappear as it advances in growth ; it may possi- 

 bly therefore be only a variety of N. biangulatus : the 

 specimens with keels are however much larger than the 

 specimen figured. All the three species appear to have 

 a deep sinus in the lip. 



The great works going on in Cork Harbour have oc- 

 casioned an immense display of the fossils of the Black- 

 Rock, among which the shell before us is one of the 

 less common. 



