PYCNODONT THETH OF UNCERTAIN GENERIC POSITION. 169 
Worn teeth; British Museum. 
Specific Characters. — Principal teeth ovoid, with gently rounded smooth 
T'ype. 
crown; lateral teeth irregularly rounded, also with low, smooth crown. 
Description of Specimens—The type specimen (Pl. XXXIV, fig. 7) comprises 
six teeth probably of the splenial dentition, all much abraded or worn and 
showing a punctate surface. The teeth of the principal series are scarcely twice 
as wide as long, while the three lateral teeth are very irregular. 
It seems probable that the vomerine dentition shown in Pl. XXXIV, fig. 8, 
belongs to the same species, although it does not clearly show the punctate 
structure where the teeth are worn. The median teeth are much less than 
twice as wide as long, and they are flanked by only one paired series, which is 
considerably destroyed by wear in the fossil. The large pulp-cavity is conspicuous 
in many of the teeth. A smaller vomerme dentition in the Capron Collection 
(B. M. no. 49803) is very similar in general character, but has the teeth more 
crowded. 
Horizons and Localities.— Probably a Turomian zone: Lewes. Chalk: Graves- 
end, Kent; Dorking, Surrey. 
4. Acrotemnus faba, Agassiz. Plate XXXIV, fig. 6. 
1837-44. Acrotemnus faba, L. Agassiz, Poiss. Foss., vol. ii, pt. 11, p. 203, pl. Ixvia, figs. 16—18. 
1887. Celodus faba, K. A. von Zittel, Handb. Paleont., vol. 1, p. 249. 
Teeth; British Museum. 
Specific Characters — Principal teeth smooth and bean-shaped, each with a 
Type. 
sharp keel-like coronal summit overhanging a sheght imdent which has a feebly 
crimped inferior margin. 
Description of Specimen.—Vhe type is still the only known specimen, and 
comprises five teeth, all similar to that shown from the oral and posterior aspect 
in Pl. XXXIV, figs. 6, 6a. These teeth probably belong to the splenial bone. 
They are noteworthy for their smooth surface of dense enamel. 
Horizon and Locality. —Chalk : Lewes. 
Prehensile front teeth of Pyenodonts are also found in the Chalk, and one such 
specimen is shown in Pl. XXXV, fig. 8. They are shghtly hooked, laterally 
compressed, and somewhat constricted at the base of the crown, which is often 
crunped. 
Among the fragments of Pycnodonts which are generically indeterminable, 
may also be mentioned the so-called Microdon occipitalis (Dixon, Geol. Sussex, 
1850, p. 369, pl. xxxii,* fig. 2). It is part of a small fish from the Chalk of 
Malling, near Lewes, in the Brighton Museum (Willett Collection, no. 104). 
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