JURASSIC FOSSILS FROM KIKUZEN. 5 



on the last whorl. Most of these ribs rise at the eds-e of the 

 steep, almost perpendicular umbilicus, but there are some which 

 commence either at a short distance from the edge or, as is 

 sometimes the case, near the middle of the lateral side. The 

 longest of these ribs are at first directed slightly forward and 

 then curve somewhat backward, and then again forward on the 

 external side, where they are interrupted by a deep narrow groove, 

 an unmistakable sign of the genus Schlotheiriiia. 



Our only specimen being not in a good state of preservation 

 does not permit its strict comparison with European species. But 

 that it is not Schlothewiia angulata to which it presents some 

 resemblance is clearly shown by the different course of the ribs. 



The genus Schlotheimia is confined in Europe to the lower 

 Lias. 



Locality : — Bandy Clavslate of Hosoura. 



2. HARPOCERAS IKIANUM n. sp. 



PI. L, Fig. 5. 



The shell fiattened and furnished with a distinct keel. The 

 whorls are tolerably convex and about S involute. The umbilicus 

 is small being only <> mm. in a shell Avhose diameter measures 

 20 mm. The umbilical wall is steep. The lateral sides of the 

 whorls bear distinct ribs which are about 40 in number on the 

 last volution. Of these 40 ribs, only about one half rise at the 

 umbilical edge, the others being formed by their bifurcation at 

 about * the distance from the umbilicus. But now and then 

 between the bifurcating ribs there is intercalated a simple rib 

 which does not reach the umbilicus. The course of the ribs may 



