COCHLIODONTID^. 
209 
Genus STREBLODUS} Agassiz. 
[Morris & Eoberts (ex Agassiz, MS.), Quart. Journ. Geol. Soo. 
vol. xviii. 1862, p. 101\] 
Posterior dental plate much inrolled ; antero-latoral border cross- 
ing the supporting cartilage at right angles, thus giving the plate 
a truncated appearance in front ; postero-lateral border inclined 
inwards and backwards, and forming an acute angle with the 
inner margin. Hinder portion of the coronal surface tumid, and 
separated more or less abruptly from the less elevated front portion ; 
the latter area often marked by small ridges and grooves proceeding 
directlj’ from the outer to the inner border. 
The dental plate just described is evidently homologous with the 
single posterior plate of Poecilodus and Deltcqttychius, and with the 
two separate posterior i)lates of Cochliodtis. In at least two species 
(S. oblongus, and the so-called upper dental plate of Ddloptychim 
wachemuthi) the separate eeries of small teeth immediately in 
advance of this large tooth is known. 
By St. John and Worthen the dental plates referred to Sirehlodus 
are considered to pertain in reality to the genera Cochliodus, Delto- 
ptychius, and Chitonodus. In one case, indeed, plates of this charac- 
ter have been found in natural association with an undoubted jaw 
of Cochliodm “ ; but there is yet no proof of their connection with 
the two last-named genera, and it thus seems advisable to retain 
Strehlodus provisionally independent, awaiting further evidence of 
the true relationships of the dental fragments on which it has been 
founded. 
Streblodus oblongus (Portlock). 
184.3. Cochliodus oblonyus, L. Agassiz, Poiss. Foss. vol. iii. p. 174 fname 
only). 
1843. Cochliodm dbhnyus, J. E. Portlock, Rep. Geol. Londonderir 
p. 4G0, pi. xiv. o. figs. 5, 10. 
18-5.5. Cochliodus oblonyus, F. M'Coy, British Palseoz. Foss. p. 623 
pi. 3 H. fig. 19, pi. 3 1, fig. 28. ’ 
1802. Streblodus oblonyus, Morris & Roberts, Quart. Joum. Geol. Soc. 
vol. xviii. p. 101 (name only). 
‘ The name only is here mentioned and applied to the species previously 
figured and described by Portlock and M Coy under the name of Cochliodus 
oblonyus. The type species being thus already well-defined in 1802, the generic 
name may be regarded as dating from that year. 
^ Cochliodus lotus, Leidy, suprh, p. 208. 
p 
