PLATE III. 
Fig. " Page 
1. Tetragonolepis semicinctus, Broun; left lateral aspect.-— 
Upper Lias; Boll. [P. 3325 b.] 160 
P. Ophiopsis attenuota , Wagner ; right lateral aspect.—Lower 
Kimmeridgian: Kelheim. [P.3609.] 167 
3. Ditto; left pectoral fin, outer aspect, thrice nat. size.— 
Ibid. x. Scale, b. Basal cartilages. [P. 1090.] 167 
4. Macrosemius rostrcitus , Agassiz; right lateral aspect.— 
Lower Kimmeridgian ; Eichstadt. [P. 7177.] 178 
5. Propterus speciosus, Wagner; right lateral aspect.—Lower 
Kimmeridgian; Solenhofen. [37088.] 184 
6. Propterus scacchii (Costa); left lateral aspect.—Upper 
Jurassic; Torre d’Orlando. [P. 3613.] 185 
7. Potagogus pentlandi , Agassiz ; left lateral aspect.—Ibid. 
[P. 2065.] 187 
8. Ditto ; portion of vertebral axis, middle of trunk of young 
individual, lateral aspect, one-third nat. size, showing 
pleurocentra and hypocentra.—Ibid. [P, 1097.] 187 
