CONTENTS. XV11 



production. Metamorphosis of " Spinula." Cynthia aggre- 

 gata. Cynthia ampulla. Astidia intestinalis p. 443-452 



CHAPTEK XLIX. 



COMPOUND ASCIDIANS. 



Composition of colony. Metamorphosis. How Compound 

 Ascidians become associated. Pyrosoma p. 453-460 



CHAPTER L. 



Alternation of generations. Organization and habits of Salpa3. 

 Phosphorescence p. 461-464 



CHAPTER LI. 



THE SCALLOP-SHELL, THE MUSSEL, AND THE LIMA. 



Structure of the Scallop. Ciliated branchiae. Faculty of loco- 

 motion. Fabrication of byssus. Habits of Lima tenera. 



p. 465-476 

 CHAPTER LIL 



SOLEN SILIQUA " THE RAZOR-SHELL." 



Excursion with Sir John Ross. Mode of fishing for the Razor- 

 shell. Uses of the "foot." p. 477-484 



CHAPTER LHI. 



PHOLAS DACTYLUS. 



Boring bivalves. Structure of siphons. How the rock is per- 

 forated. Phosphorescence of Pholades. Prodigious fertility 

 of the Conchifera p. 485-493 



CHAPTER LIV. 



GASTEROPOD MOLLUSCA. 



A remonstrance. Foot of Gasteropods. Aplysia, "the Sea- 

 hare." A suspicious character. Food and habits of Aplysia. 



