526 THE ORIGIN OF VERTEBRATES 



Germ-cells, 471 

 Giant-fibres, 489 

 Gigantostraca, 25, 234 

 Gills, 148, 161, 185, 214, 494 

 Glabellurn, 339 

 Glands, carotid, 427 



coxal, 242, 246, 319, 321, 425, 429 



ductless, 418 



generative, of Limulus, 209 



internal secretion of, 214 



lymphatic, 418 



pineal, 15, 63, 75, 456 



pituitary, 244, 246, 319, 425 



segmental, of Crustacea, 422 



submaxillary, 466 



sweat, 448 



thymus, 425 



thyroid, of Aminoccetes, 193, 194, 196, 201, 205, 429 



tissue round brain of Ammoccetes, 209, 379 



uterine, of Scorpion, 202, 203, 204, 205 

 Gnathostomata, 60, 343 

 Goblet, 359, 360, 373 

 Goitre, 215 

 Gonad, 475, 479 

 Gonoccele, 475, 481 

 Grooves, ciliated, 188, 197, 212 



,, hyper-pharyngeal of Amphioxus, 410 

 ,, ventral, of apus and trilobites, 436 

 Gymnophiona, 393 



Hjemocytes, 472 

 Head of embryo dogfish, 121, 123 

 Head-shield, dorsal, of Ammoccetes, 330, 331, 338 

 ,, ,, Auchenaspis, 29, 31, 338 



Cephalaspis, 327, 328, 330, 338, 348 

 ,, „ Cyathaspis, 340 



,, ,, Didyniaspis, 338 



,, „ evidence of segmentation, 339 



,, ,, Keraspis, 328 



„ ,, Ostreostraci, 327, 348 



,, ,, Palseostracan, 348 



„ ,, Pteraspis, 29 



Thyestes, 29, 31, 327, 332, 338, 340, 341, 348 

 ,, ventral, Scaphaspis, 349 



Heart, nerves, 2, 447 



,, origin of vertebrate, 179, 451, 459 

 ,, relative position in vertebrate and invertebrate, 175 

 „ veins forming vertebrate, 180 

 Hemiaspis, 24, 25, 249, 250, 351, 414 

 Hemispheres, cerebral, 47 

 Hepatopancreas of Ammoccetes, 452 

 ,, Limulus, 211 



