Question

Hagfish is another name for
A. Petromyzon
B. Lamprey
C. Myxine
D. Cephalaspis

Answer 1

Hint: Hagfish are eel-shaped, slimy marine fish which is often also known as slime eels.These fishes are also an example of only living animals which have a skull but no vertebral column.

Complete answer:
Let us look at each option one by one.
Option A: Petromyzon or sea lamprey (also called vampire fish) are parasitic fish native to the northern hemisphere. It has numerous hollow teeth more than what the hagfish has. Clearly, there are differences between Petromyzon and Hagfish; thus, this option is incorrect.

Option B: Lampreys are an ancient lineage of jawless fish which are often mistakenly called lamprey eels. They belong to the order petromyzontiformes. We can see that options (A) and (B) refer to the same organism which is significantly different from Hagfish. Therefore, this is an incorrect option.

Option c: Myxine glutinosa is an organism of the order Hagfish. They are long and worm-like organisms which release large amounts of slime or mucus. Myxines are vertebrates which have a skull but lack the vertebral column. Thus, hagfish is another name for myxine. Therefore, this is the correct option.

Option D: Cephalaspis is an extinct monotypic genus of osteostracan agnatha vertebrates. They were detritivorous fish i.e., they ate dead or decaying plants and animals for food. The characteristics of this fish does not match with those of hagfish. Thus, this option is incorrect.
Therefore, the correct answer is (C) Myxine.

Note: All the aquatic organisms mentioned in the question belong to the superclass Agnatha under the subphylum Vertebrata of the phylum Chordata. The superclass Agnatha lists all the jawless fish.