Page:Ann. Lyc. Nat. Hist. 11 155-162.djvu/8

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162
Ceraurus pleurexanthemus.

EXPLANATION OF PLATE XI.

Figure A. Section of thorax at fourth segment; enlarged to two diameters.
a. Axial groove.
bb. Axial processes.
cc. Thoracic pleuræ and triangular depressions.
dd. Circular cavities.
ее. Free pleuræ.
gg. Inner extremities of thoracic pleuræ.
Figure B. Interior of the dorsal shell; enlarged to two diameters.
1. Hypostomatic suture.
2. Hypostoma.
3. "Doublure."
4. Occipital depression.
5. Occipital cavity.
6,7. Facial sutures cutting "doublure."
8. Glabellar depressions and processes.
9. Neck depression.
10. Spines of the head.
a. Axial groove.
bb. Axial processes.
cc. Triangular depressions.
dd. Circular cavities.
ее. Free pleuræ.
f. Crescent shaped surface on free pleuræ.
m. Elevated margin of the hypostoma.
rr. Axial processes.
s. Smooth crescent-shaped surface on "doublure."
t. Pygidium.
x. Oval openings.
z. "Doublure."
Figure C. Longitudinal section at median line; enlarged to two diameters.
1. Hypostomatic suture.
2. Hypostoma.
3. "Doublure."
4. Head.
5. Thorax.
6. Pygidium.
Figure D. Section of segment at median line; enlarged to five diameters.
1. Posterior reflected articular margin.
2. Outer surface of segment.
3. Union of articular fold and axial ring.
4. Articular fold.