X CONTENTS. 



CHAP. XV. 



BAYED ANIMALS SEA-URCHINS. 



Antiquity of the Race. Egg-urchin. Complexity of Struc- 

 ture. Method of Enlargement. Mechanism of Spines, of 

 Mouth, &c Page 231 



CHAP. XVI. 



ARTICULATA, OB JOINTED ANIMALS MARINE "WORMS, ETC. 



Their Structure. Tubicolse and Serpulae, &c. Nereis. 

 Sea-mouse 239 



CHAP. XVIL 



ARTICULATA, OB JOINTED ANIMALS CIRRIPEDA. 



" Curl-footed " Animals. Balanus or Acorn-shelL Barnacles. 

 Pentalismus anatifera. Popular Error. Young of the 

 Barnacle Shell, &c 249 



CHAP, xvm 



ARTICULATA CRABS. 



Structure. Spider-Crab and various other Species. Pagurus : 

 Habits and Structure, &c. Zoea 257 



CHAP. XIX. 



ARTICULATA LOBSTERS, ETC. 



The Shrimp. The common Lobster. Various Species. 

 Structure and Habits, &t. 273 



CHAP. XX. 



MOLLUSCA, OR SOFT-BODIED ANIMALS BIVALVES. 



Molluscs. Bivalves. Structure and Habits of various Spe- 

 cies. The common Cockle, &c 283 



CHAP. XXI. 



MOLLUSCA WHELKS. 



The Whelk and its Varieties. Structure and Instincts, &c. 

 The Limpet. Structure, &c 293 



