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