PLATE XVI. 
Fig. Page 
1. Mesodon macropterus (Agassiz) ; left lateral aspect, two- 
thirds nat. size.—Lower Kimmeridgian ; Eichstadt. 
h. Pectoral basals. fr. Frontal, o. Orbit, op. Oper¬ 
culum. p op. Preoperculum, pa. Parietal. s.occ. 
Supraoccipital. sq. Squamosal, v. Vomer, x. Process 
of parietal. [P. 5546.] 200 
2. Gyrodus frontatus , Agassiz ; lateral aspect.—Lower Kim¬ 
meridgian ; Kelheim. hr. Branchiostegal rays. cl. 
Clavicle, fr. Frontal, g.f. Gill-filaments, h. Haemal 
spines, n. Heural spines, op. Operculum, p. Lobe 
of pectoral fin. p.op. Preoperculum. plv. Pelvic fin- 
support. scl. Sclerotic, sq. Squamosal, t. Tesserae. 
x . Problematical post-abdominal bone. [P. 2097.] 236 
3. Gyrodus hexagonus (Blainville); fragment of right side 
showing Hyomandibular (Jim.), Operculum (op.), and 
Preoperculum (p.op.). —Lower Kimmeridgian ; Solen- 
hofen. [37108.] 235 
4. Coccodus armatus, Pictet; cranium, right lateral aspect.-— 
Upper Cretaceous; Hakel. [39227.] 268 
