However , these alterations were not grounded within evolutionary theory .
Fish lacking this appendage were placed within the order Apodes ; fish containing abdominal , thoracic , or jugular pelvic fins were termed Abdominales , Thoracici , and Jugulares respectively .
These alterations were not grounded within evolutionary theory .
Fish lacking this appendage were placed within the order Apodes ; fish containing abdominal , thoracic , or jugular pelvic fins were termed Abdominales , Thoracici , and Jugulares respectively .