PLATE 22.— Fish-scales, etc. 



Figure 



1. Scale of sturgeon, perpendicular section, a, outer spongy portion ; b, inner 



laminated portion ; 1 c, transverse section of outer portion. 



2. Skin of thornback skate (JRaia clavata), viewed from above. 



3. Large spine of skate, side view. 



4. Portion of transverse section of large spine of skate (fig. 3 6). 



5. Longitudinal section of tooth of a small spine of skate (fig. 2). 



6. Scale of perch (Perm fluviatilis). 



7. Perch-scale, portion of (fig. 6 a), more magnified. 



8. Perch-scale, portion of (fig. 6 b), more magnified. 



9. Scale of sole (Solea vulgaris). 



10. Scale of roach (Leuciscus rutilus). 



11. Scale of roach (Leuciscus rutilus), portion of surface more highly magnified. 



12. Scale of roach (Leuciscus rutilus), perpendicular section. 



13. Scale of minnow (Leuciscus phovinus). 



14. Feather of finch ; shaft with medullary cells. 



15. Feather of goose (Anser cinereus). a, pinnae with hooks ; b, pinna? with teeth ; 



c, barbs. 



16. Separate pinnae, a, with hooks ; b, with teeth. 



' ' [ Feather (downy), free barbs of. 



18. J 



19. Skin of eel (Anguilla vulgaris), with stellate pigment-cells, and indications of 



subjacent scales. 



20. Scale of eel (Anguilla vulgaris). 20 a, portion, more magnified. 



21. Calcareous corpuscles from the same, left after red heat. 



22. Scale of jack or pike (Eso.v lucius). 



23. Scale of dace (Leuciscus vulgaris). 



25. Leech (Hirudo medicinalis), anterior sucker of. 



26. Leech, jaw of, side view, a, b, teeth ; c, fibro-cartilaginous substance of jaw ; 



d, pigment-cells. 



27. Leech, jaw of, the free margin turned towards the observer. 



28. Leech, teeth of. a, side view ; b, front view. 



29. Horn of cow. a, section parallel to surface ; b, cells softened by potash ; d, con- 



taining pigment ; e, perpendicular section ; /, cracks between laminae ; g, edges 

 of divided laminae. 



30. "Whalebone, longitudinal section. 



31. Whalebone, transverse section. 



32. Whalebone, longitudinal section of hair of. 



33. Whalebone, cells of, resolved by potash. 



34. Fish, crystals from scales of. 



35. Muscular fibres of lobster (Astacus marinus). 



36. Muscular fibrillae, various appearances presented by (p. 525). 



37. Large spine of skate, outer portion of. 



