SOME NEW SPECIES OF AMMONITES. 



145 



The small specimen has the greater portion of the test preserved, 

 and also shews the mouth-border. 



Locality, Oborne, Dorset, where it is fairly common. 



Position, zone of Stephan. Humphriesianum. 



Nearest Allied Form. Perisphinctes Martinsii d'Orb. Our 

 species, however, differs from it in being far flatter, with 

 broader whorls and greater inclusion. 



[Dr. Wright, in the Journal of the Palseontological Society 

 for 1880, figures on page 254 Periophinctes Martinsii with a 

 large amount of inclusion, but I cannot agree with it. If it is 

 compared with d'Orbigny's figure in Palaeont. Frangaise, plate 

 125, Cephalopodes, it will be seen to be very different.] 



HARPOCERAS BOWERI (J. BuclcmanJ, woodcut figure in text. 

 AMMONITES BOWEEI, /. Buckman, M.S. 



1. HABPOCEEAS BOWEEI, natural size. 



Shell somewhat compressed ; whorls about one-half included ; 

 ornamentation, plain small slightly bent ribs, without bifurca- 

 tions ; mouth-border possesses two fine labial prolongations, and 

 is somewhat produced on the ventral area, in which respect it 

 differs from the mouth-borders of the genus Stephanoceras ; 

 ventral area ornamented with a very small keel which is not so 

 conspicuous on the body-chamber. 



