NATURAI, HISTORY OF AMERICAN LOBSTER. 151 



Paga 

 Chapter VI. Anatomy of the lobster, with embryological and physiological notes — Continued. 



Sense organs 232 



Eyes 232 



Sensory hairs 234 



Relation of setae to hatching and to molting 235 



Touch, taste, and smell 236 



Balancing organs or statocysts 238 



Muscles 241 



Blood and organs of circulation 242 



Heart 243 



Pericardial sinus 243 



, Arteries 244 



Arterial supply of the swimmerets 245 



Gills 246 



Branchial cavity and respiration 247 



Course of the blood in the gill 248 



Alimentary tract 249 



Grinding stomach 249 



Liver 251 



Kidneys or green glands 252 



VII. The great forceps, or big claws 253 



The crustacean claw 253 



The great chelipeds 254 



Lock hinges of big claws 255 



Asymmetry in the big claws of the lobster 256 



Torsion of the limb 257 



Breaking plane and interlock 259 



The toothed claw or lock forceps, and its periodic teeth 260 



The cracker, or crushing claw 264 



Development of the great forceps 266 



Variation in position of the great forceps 274 



Symmetry in the big claws 275 



Changes in the toothed claw at molting 278 



VIII. Defensive mutilation and regeneration 281 



Autotomy or reflex amputation 281 



Restoration of lost parts 283 



Monstrosities 285 



IX. Reproduction 288 



Sexual distinctions 288 



The ripe ovary 289 



Development of the ovary to the first sexual period 290 



Cyclical changes in the ovary after the first sexual period 291 



Disturbances in cyclical changes in the ovary 292 



*^ — Period of adult life or sexual maturity 293 



« — Limits of the breeding season 294 



<f-~ Frequency of spawning 295 



*~ Number of eggs produced 298 



Breeding habits and behavior in crayfish 300 



<. — Pairing habits in the lobster 302 



Preparation for egg laying: Cleaning brushes of the lobster 303 



«— Egg laying 305 



