DESCRIPTION OF FISHES. 197 
in each lateral margin; the true maxillary teeth being extremely small, and 
inadequate to destroy and secure its prey. But with this strong beak the Pristis 
is said to attack successfully even the larger cetacea. This genus was formerly 
placed with the Squalide, but Professor Agassiz considers the family of Ratide to 
have a stronger claim for its relationship. 
Sphyrenodus, a genus formed by Agassiz.—The remains of one species, 
S. priscus, are occasionally found at Sheppey ; at Bracklesham they may be con- 
sidered very rare fossils. A magnified view showing the beautiful structure of 
the tooth of this genus is given in Professor Owen’s ‘ Odontography,’ pl. 54, 
under the name of Dictyodus. 
Species of the recent genus Sphyrena exist in the Mediterranean, and are 
abundant in the Brazilian and American seas; they are considered more vora- 
cious than sharks, and particularly greedy of human flesh. 
Siluride.—These fish are furnished with a strong dorsal defensive bone, and 
the first ray of the pectoral fin is composed also of a strong spine attached to 
the scapular arch or shoulder-bone ; both these weapons are so articulated as to 
be erected or depressed according to the will of the animal. They frequent 
rivers, estuaries and lakes. 
The dental remains of fish are much sought after by Paleontologists, being 
not only beautiful objects in themselves, but often the only indications of extinct 
species: they prove also the existence of a contemporaneous assemblage of 
plants and animals which must have supplied them with food. 
Order CARTILAGINEI, Cuv. (PLACOIDEI, Agassiz.) 
Suborder RAIID, Miiller. 
Genus Myliobates. 
Myliobates.—The remains of the dental apparatus of these fish furnish some 
of the most interesting fossils of Bracklesham ; they are commonly called 
‘palates,’ and are found lying loose on the exposed surface of the London-clay 
formation, more especially after high and rough tides, and at the western part 
of the bay. Detached dental plates are very common, but good specimens 
with 6 or 7 rows are rare. I have during the last ten years collected a great 
variety of these curious crushing teeth, the specimens varying from half an inch 
2D 
