PLATE rX. 
Fig. P"«« 
1 . Jhjhodus niedius, Agassiz : remains of tho iicad ami denti- 
tion, left lateral as])ect, (wo thirds nat. size. L. Lias; 
Lyme llegis. c.s. Cephalie spines, md. Left ramus of 
mandible. Left i)terygo-quadratc, obscured by 
shagreen, i.-viii. Successive dental series of the lower 
jaw. [41103.] 
2. Ditto; tooth with cleft summit, lateral aspect. — ll)id. 
[36881.] 2()5 
3. Ditto ; tooth dividtal near one extremity, lateral aspect. — 
Ibid. ’ [P. 2794.] 200 
