Chapter 25, Problem 3FTB

Summary Introduction

To review:

The given blank space in the statement, “both gills and lungs are present in adult _______. Sharks and rays have internal skeletons composed of _______. The vertebrate group with the largest number of species is ________. Lampreys have teeth but lack ________.”

Introduction:

The gills are the distinguishing features of fishes, while the lungs are mostly found in the members of the higher class of vertebrata. The sharks and rays do not possess a swim bladder, unlike other fishes. The lampreys and the hagfishes are considered to be sisters taxonomically. The term cyclostomes are used collectively for both these fishes. Both these fishes have an eel-like elongated body and lack the usual fins, which occur in the fishes.