cxx INFERIOR OOLITE AMMONITES. 



than that of Deltoidoceras idonewm. More of the inner whorls is exposed than in 

 that species, and the inner marginal edges are much more pronounced. 



Locality and Stratum. — Dorset : Bradford Abbas, Fossil Bed, evidently upper 

 part. This fine example of a most distinctive species is unique. It is from the 

 collection formed by Mr. Darell Stephens, F.Gr.S. 



Date of Existence. — Discitas hemera. 



2. Nonsepticarinate. 



2. Deltotoceeas teiangulaee, S. Buclnnan. Sup pi., Fig. 84 in text. 



Distinction. — From D. discoideum (Quenstedt), the stouter, more definitely trian- 

 gular whorls. From D. cuneatum, the smaller umbilicus. 



a b 



Fig. 84. — Deltotoceras triangulate ; a, Section ; b, Eadial line and umbilicus. 



Locality and Stratum.. — Dorset: Bradford Abbas, Fossil Bed, evidently upper 

 part (Collection of Mr. D. Stephens). 

 Date of Existence. — Discitse hemera. 



3. Deltotoceeas aff. discoideum (Quenstedt). 



1889. Hypbrlioceras discoideum, This Monogr., pp. 98 — 100. Some of the 



remarks on p. 99 about the carina refer to 

 this form. 



Remarks. — The figures of H. deflexvm (olim H. discoideum, p. 98) Plate XIX, 



