16 The Exterior of the Fish 
Fic. 7.—Porcupine-fish, Diodon hystrix (Linneus). Tortugas Islands. 
Ve 
Fic. 8. 
Fic. 8.—Thread-eel, Nemichthys avocetta Jordan and Gilbert. Vancouver Island. 
Fic. 9.—Sea-horse, Hippocampus hudsonius Dekay, Virginia. 
