HABITS, ETC., OF CEREBRATULUS LACTEUS. 



97 



The Habits and Early Development of Cere- 

 bratulus Lacteus (Verrill). 



A Contribution to Physiological Morphology. 



By 

 Clias. B. IVilson. 



With Plates 9—11. 



Outline. 

 I. Introduction .... 

 II. The Adult Worm. 



A. Determination of Species 



B. Habitat and Habits : 



(1) Geographical distribution 



(2) Burrows and burrowing 



(3) Food .... 



(4) Breathing 



(5) Locomotion . 



(6) Dismemberment 



(7) Regeneration . 

 III. Larval Development. 



A. Sexual Organs: 



(1) The ovaries : 



(a) Germ tissue . 



{b) Oogenesis 



(e) Formation of oviduct . 



(2) The testes : 



(a) Sperm tissue . 



{d) Spermatogenesis 



(c) Formation of sperm-duct 



B. Egg-laying 



c. Fertilisation and Ripening : 



(1) Fertilisation . 



(2) Formation of polar bodies 



(3) Activities of polar bodies : 



(a) Description of activities 



(b) Connection with egg . 



(c) Polarisation 



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