524 THE ORIGIN OF VERTEBRATES 
Epithelium cells of Ammoccetes, 347 
35 of central nervous system of vertebrates, 38, 457 
5 ccelomic spaces in annelids, 421 
x optic diverticula, 103 
ra peritoneal, pleural, and pericardial cavities, 477 
“5 velum of Ammoccetes, 301, 302 
Equilibration, 358 
Kukeraspis, 326 
Eurypterus, 26, 150, 191, 237 
3 appendages, 150, 236, 237 
- classification, 249 
8 comparison with Ammoccetes, 170, 323 
5 diagram of sagittal median section, 240, 245 
A endostoma, 241, 306 
eyes, 275 
45 mesosomatic segments, 192 
45 muscles of carapace, 269 
operculum, 150, 190, 212 
Evidence of alimentary canal, innervation, 446 
‘i auditory apparatus and lateral line organs, 355 
¥§ coelomic cavities in Limulus, 251 
3 degeneracy in Ammoceetes, 59, 94, 343 
a embryology, cartilage, 20, 129 
si a eye-muscles, 263 
4 "9 excretory organs, 390 
9 43 heart, 179, 451 
ey 3 nervous system, central, cerebral vesicles, 48, 458 
a +5 bs i 3 epithelial tube, 37, 42, 102, 244, 433, 
455 
os 5 - neurenteric canal, 37 
+ = (i 6 a neuropore, 220, 457 
5 “4 Ms 5 4 optic diverticula, 102 
spinal cord, 46 
etal chaiioar, 228, ‘042, 243, 290 
i” a olfactory organ, 220, 227 
palzeostoma or old mouth, 317 
pineal or median eyes, 15, 63, 74, 456 
pituitary body and coxal glands, 246, 319 
thyroid, 192, 194 
55 Se segmentation, double, of head, 157, 234, 258 
ii $i skeleton, cranial, 120, 153 
nervous system, central, 8 
$5 notochord, origin from segmented region, 443 
6 olfactory apparatus, 218 
a organs of vision, 68 
6 paleontology, 20, 497 
8 pineal or median eyes, 74 
a prosomatic musculature, 247 
5 respiratory apparatus, 148 
Pr segmentation in head-shield, 339 
skeleton, 119 
Rivolution, 8, 15, 20, 149, 482, 497 
