SC0MBRIDJ3. 
473 
24613. Cranium probably of this species, with large patch of 
vomerine teeth transversely expanded ; Sheppey. 
Purchased, 1850. 
38922-23. Two other crania, the first showing normal vomerine 
teeth, the second very imperfect; Sheppey. 
Bowerhank Coll. 
Genus SPHYR.ffiNODUS, Agassiz. 
[Poiss. Foss. vol. V. pt. i. 1844, p. 98.] 
—o/ 
An extinct genus comprising large species known only by portions 
of skull and dentition. Teeth large and conical, not laterally 
compressed, in single series on margin of jaws [and on palatine bone, 
according to Dollo and Storms]. 
The dentition is more powerful and the premaxillae are relatively 
larger than in the existing genus Pelamys. 
Sphyraenodus priscus, Agassiz. 
1841. Sphyrcenodus prisons {Dictyodus), It. Owen, Odontogr.’p. 120, 
pi. liv. 
1839-44. Sphyrcenodus prisons, L. Agassiz, Poiss. Foss. vol. v. pt. i. 
p. 98, pi. xxvi. figs. 4-6. 
1890. Diotyodus prisons, Woodward & Sherboru, Catal. Brit. Foss. 
Vert, p. 64. 
Type. Jaws and associated remains ; British Museum. 
The type species, with mandible attaining a length of 0*16. 
Jaws much elongated, the maximum depth of the mandibular 
ramus contained about four times in its length. Teeth plicated at 
the base, slightly incurved at the apex, remarkably uniform in 
size. 
Form. Loc. Lower Eocene (London Clay): London Basin. 
P. 3957. Type specimen, described and figured by Agassiz, loc.cit. ; 
Sheppey. Only obscure fragments of the cranium are ^ 
shown. Enniskillen Coll. 
An undescribed species of Sphyrcenodus also occurs in the Middle 
Oligocene of Boom, near Antwerp (^Dictyodus rupeliensis, Dollo & 
Storms, Zool. Anzeig. 1888, p. 266). 
The generic name Diotyodus, Owen (Bep. Brit. Assoc. 1838 
[1839], Trans. Sect. p. 142), was considered as a synonym of 
Sphyrcenodus by Owen, Odontogr. (1841), expl. pi. liv.; but it 
seems to have been based on some fragmentary jaws in the Boyal 
