Fig. 80 



SL 



Figs. 80-82. Pterichthys testudinarius, Ag. ; restored by R. H. TRAQUAIR, from the 

 dorsal aspect (80), ventral aspect (8i),and lateral aspect (82). The double dotted lines 

 indicate the grooves of the sensory canal system ; and in the trunk, the thick lines repre- 

 sent the exposed borders of the plate, the thin line showing the extent of the overlap. 



ADL. Anterior dorso-lateral. AMD. Anterior median dorsal. A VL. Anterior ventro- 

 lateral. EL. Extra-lateral (or operculum). L. Labial. MOCC. Median occipital. PM. 

 Premedian. PDL. Posterior dorso-lateral. PMD. Posterior median dorsal. PVL. Pos- 

 terior ventro-lateral. SL. Semilunar. (Figure from SMITH WOODWARD.) 



68 



