they have seven gills made of cartilage which are attached onto modified lungs
with gills; they're fish!
through holes in there body. who knows what ones... probably all of them....
Externally
skin
without jaws
Agnatha, also known as jawless fish, lack jaws and scales. They have a cartilaginous skeleton, a round mouth, and a single nostril on their head. Agnatha are also known for their ability to produce slime as a defense mechanism.
by the gill slits
Class Agnatha
jawless fish. not very common today, but they were in the past.
no they have large bonelikes structures called the stonnes.
I don't know but i will do some research...
Agnatha, such as lampreys and hagfish, have a two-chambered heart. The heart consists of an atrium and a ventricle, which pump blood through the circulatory system.