EXPLANATION OF PLATES. 
All figures were drawn with the aid of an Abbé camera lucida, from specimens 
of Lepidosteus osseus, L. 
ABBREVIATIONS. 
ba. spi. Base of spine. mb. gan. Ganoin membrane. 
can Canal. nl. Nucleus. 
chr’ ph. Chromatophore. od’ bl. Odontoblast. 
drm f’br. Fibrous portion of dermis. pap. spi. Spine papilla. 
drm. spng. Spongy ss it pig: Pigment. 
Sac. Surface. Sc. Scale. 
fac. e'drm. Surface of ectoderm. scl’bl. Scleroblast. 
Sor. Foramen. spi. Spine. 
gan. Ganoin. tbl. de. Dentinal tubule. 
gin Gland, first kind. tbl. ipd. “ Lepidine tubule.” 
gin. Gland, second kind. vs. sng. Blood-vessel. 
mb. ba. Basement membrane. 
