Agnatha are ancient jawless fish that include lampreys and hagfish. They are also probably the earliest vertebrates and have ectoderm.
Agnatha is a superclass of the phylum Chordata. It contains the jawless fish. Two common examples of this would be the lamprey and the hagfish.
agnatha excrete(expulse non-needed matter) by using a propulsory system called the anal ejector. they usually excrete this matter during copulation in the form of sperm wikipedia has this answer too
circulation
Its Chondrichthyans and it depends on the species. Mostly they are ectothermic but a small number of exceptions exist. Some sharks, like the thresher shark, can warm parts of its body some what, this means a few C above water temperature not like how warm blooded animals regulate temperature. So in short.Ectothermic.
Externally
Agnatha is a superclass of the phylum Chordata. It contains the jawless fish. Two common examples of this would be the lamprey and the hagfish.
Agnatha are ancient jawless fish that include lampreys and hagfish. They are also probably the earliest vertebrates and have ectoderm.
skin
without jaws
Class Agnatha
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.
by the gill slits
with gills; they're fish!
I don't know but i will do some research...
jawless fish. not very common today, but they were in the past.
no they have large bonelikes structures called the stonnes.