450 



INDEX — GLOSSARY 



Visceral, pertaining to the viscera, the 

 organs of the abdomen, such as 

 stomach and intestines. 



Visceral arch, first, 33Q; hyoid, 339; 

 mandibular, 339 ; second, 339. 



Visceral ganglia, in gastropods, 237 ; 

 in pelecypods, 221. 



Visceral spiral, in gastropods, 234, 23s. 



Viscero-pedal mass, 210. 



Vitreous humor of eye, 334. 



Viviparous, 374. 



Viviparous elasmobranchs, 339 ; ichthy- 

 osaurs, 358; mammals, 374; plesio- 

 saurs, 356 ; teleostomes, 339. 



Vocal cords, 333. 



Voice, development of, 333. 



Voice box, 326, 330, 333. 



Voltzia, 73. 



Voluntary muscles, 329, 331. 



Vorticella, 95. 



Walnut, 77; relative of, 81. 



Walruses, 381. 



Wasatch formation, fossils from, 384, 

 385, 395; geologic age of, 384, 385, 

 395- 



Washita formation, fossils from, 227 ; 

 geologic age of, 227. 



Wasps, 78, 319. 



Water fleas, 304. 



Water vascular system, of Asterias, 150 ; 

 of echinoderms, 148; of starfish, 150. 



Wave-marks, fossil, 21. 



Whales, 398-399 ; beaked, 399 ; com- 

 pared to ichthyosaurs, 358 ; derivation 

 of, 358; evolution of, 399; fin, 399; 

 food of, 247 ; geologic range of, 399 ; 

 gray, 399; habitat of, 374; hump- 

 backed, 399 ; parasites in, 305 ; right, 

 399 ; sperm, 399 ; subdivision of, 399 ; 

 toothed, 399 ; whale-bone, 399. 



Wheel-worms, 141. 



White ants, 318. 



Whorl, a single circle of leaves or a turn 



of a shell ; in leaves, 50, $5 ', in Pro- 

 tozoa, 91. 



Wielandiella, 65. 



Williamsonia, 65. 



Willow, 77. 



Wings, of birds, 369; of flying reptiles, 



364- 



Wish bone, see clavicle of birds. 



Wolf, Tasmanian, 378. 



Wombats, 378. 



Wood, fossil, 68, 71, 70; petrifaction of, 

 II— 12. 



Worms, 140-147; burrows of, 16; im- 

 pressions of, 18. 



Wrist, the carpus, 327. 



Wrist bones, see carpal bones. 



Xenophyophora, 88. 



Xiphosura, 309, 31 1-3 12; geologic 



range of, 311; resemblance to trilo- 



bites, 311. 

 Xylem, 7g. 



Yeast, 40. 



Yellow fever, 84. 



Yew, 70. 



Yolk, variation in fish eggs, 339. 



Zamites, 66. 



Zeuglodon, 399. 



Zeuglodontia, 399. 



Zoantharia, 129, 130, 131, 131-134. 



Zoarium, 173. 



Zooea, the larval stage in which the 

 young of crabs are hatched. (The 

 nauplius stage is passed through in the 

 egg.) It consists of an enormous 

 cephalothorax produced into spines, 

 large stalked eyes and a long slender 

 abdomen, 285. 

 Zooecium (plu. zooecia), 173, 174, 176. 

 Zostera, 75. 



Zygapophysis, 326 ; anterior, 326 ; 

 posterior, 326. 



Printed in the United States of America. 



