520 THE ORIGIN OF VERTEBRATES 



Arthropoda, resemblance to ancient fishes, 29 

 Astacus, brain, 54 



„ digestive ferment in cells lining the carapace, 442 



,, optic chiasma, 101 



,, optic stalk, 91 



,, retina, 98 

 Asterolepis, 326, 342 

 Atrium, 410 



Auchenaspis (Thyestes), 30, 31, 75, 275, 326, 327, 328, 338 

 Auditory apparatus, 355 

 Auerbach, plexus of, 447 

 Aurelia, 475 

 Autonomic nerves, 3 



Balanoglossus, 12, 12, 433, 438, 494 

 Bdellostoma, 394, 405 

 Belinurus, 24, 249, 351 

 Bird, rhomboidal sinus, 46 

 Bladder, 449 



„ swim, 148 

 Blastula, 459, 471, 473 

 Blood, 463, 472, 474 



„ circulation, in Ammoccetes and Limulus, 174 

 ,, secretion of ductless glands into, 418 

 Bothriolepis, 29, 32, 239, 326, 351, 450 

 Bone, 344, 474, 481 

 Brain, Ammoccetes and Arthropod, 54, 61 



,, and brain-case of Ammoccetes, 40, 41, 46, 209 

 ,, caudal, of Thelyphonus, 450 

 ,, epithelial lining of, 38 

 ,, roof, 39 



,, Sphseroma serratum, 62, 90 

 ,, Thelyphonus, 56 

 ., ventricles, 4 

 ,, vesicles, 48 

 Branchial basket-work of Ammoccetes, 126, 128, 296, 331, 335 

 Branchipus, 28 



,, brain, 51, 54 



,, eyes, lateral, 88 



„ ,, retina of, 91, 97 



,, ,, median, 75 



,, excretory organs, 396 



„ (Artemia) diverticula of gut and retinal ganglion, 110, 111, 113 



,, nerves of appendages, 157 



,, segmentation, 159 



,, resemblance to Trilobite, 436 



Bunodes, 24, 30, 249, 341, 351, 414 

 Bundle of Meynert, 48, 77 

 Bundles, posterior longitudinal, 489 

 Buthus, muscles, 270 



Calcification in aponeuroses of Cephalaspis, 414 



