xxiv List of Illustrations 



PAGE 



Notropis whipplii, Silver -fin 457 



Gymnothorax moringa 458 



Seriola lalandi, Amber-fish 458 



Geological Distribution of the Families of Elasmobranchs 459 



"Tornaria" Larva of Glossobalanus minutus 463 



Glossobalanus minutus 464 



Harrimania maculosa 465 



Development of Larval Tunicate to Fixed Condition 471 



Anatomy of Tunicate 472 



Ascidia adharens 474 



Styela yacutatensis 475 



Styela greeleyi 476 



Cynthia superba 476 



Botryttus magnus, Compound Ascidian 477 



Botryllus magnus 478 



Botryttus magnus, a Single Zooid 479 



Aplidiopsis jordani, a Compound Ascidian 479 



Oikapleura, Adult Tunicate of Group Larvacea 480 



Branchiostoma calijorniense, California Lancelet 484 



Gill-basket of Lamprey 485 



Polygnathus dubium 488 



Polistotrema stouti, Hagfish 489 



Petromyzon marinus, Lamprey 491 



Petromyzon marinus unicolor, Mouth Lake Lamprey 492 



Lampetra ivilderi, Sea Larvae Brook Lamprey 492 



Lampetra ivilderi, Mouth Brook Lamprey 492 



Lampetra camtschatica, Kamchatka Lamprey 495 



Entosphenus tridentatus, Oregon Lamprey 496 



Lampetra ivilderi, Brook Lamprey 505 



Fin-spine of Onchus tenuistriatus 509 



Section of Vertebrae of Sharks, showing Calcification 510 



Cladoselache jyleri 514 



Cladoselache jyleri, Ventral View 515 



Teeth of Cladoselache jyleri 515 



Acanthoessus wardi 515 



Diplacanthus crassissimus 517 



Climatius scutiger 518 



Pleuracanthus decheni 519 



Pleuracanthus decheni, Restored 520 



Head-bones and Teeth of Pleuracanthus decheni 520 



Teeth of Didymodus bohemicus 520 



Shoulder-girdle and Pectoral Fins of Cladodus neilsoni 521 



Teeth of Cladodus strialus 522 



Hexanchus griseus, Griset or Cow-shark 523 



Teeth of Heptranchias indicus 524 



