CONTENTS xv 



PAGE 



Class 3. The Myriapoda 239 



Example of the Class Scolopendra morsitans . . . 239 



Class 4. The Insecta 241 



Example of the Class Periplaneta americana . . 241 



Class 5. The Arachnida 254 



Example of the Class Scorpio 254 



SECTION XI 



PHYLUM MOLLUSCA . . 264 



Class i. The Pelecypoda 265 



Example of the Class Anodonta cygnea . . . 265 



Class 2. The Amphineura 281 



Example of the Class Chiton spinosus .... 281 



Class 3. The Gastropoda 284 



Example of the Class Helix nemoralis .... 284 



Class 4. The Cephalopoda 296 



Example of the Class Nautilus pompilius . . . 298 



SECTION XII 



PHYLUM CHORDATA 310 



Subphylum i. The Adelochorda 311 



Example of the Subphylum Balanoglossus . . .311 



Subphylum 2. The Urochorda 314 



Example of the Subphylum Ascidia . . . .314 



Subphylum 3. The Vertebrata 322 



Examples of the Subphylum Amphioxus, Petromyzon, 



Pisces, etc 322 



Division A. The Acrania 323 



Example of the Division Amphioxus lanceolatus . . 323 



- Division B. The Craniata 328 



Examples of the Division, the dogfish, lizard, and rabbit . 328 



Class i. Cyclostomi 360 



Example of the Class Petromyzon marinus . . . 360 



Class 2. Pisces 365 



Examples of the Class Sharks, perch, and lung fishes . 365 



