Simplify the following text for a Grade 6 native English-speaking person.
Original: Except for two lungless species â '' Atretochoana eiselti and Caecilita iwokramae â '' all caecilians have lungs , but also use the skin or the mouth for oxygen absorption .
Simplified: Most Caecilians have lungs . So far , only one species named Atretochoana eiselti is known that does not have lungs .