296 



North American Sjjecies of Petromyzoniidce. 



RECAPITULATION. 



Genus 1. — Bathymyzon Gill. 

 (Doubtful genus ; possibly based on a mutilated Pelromyzon ?) 



1. Bathymyzon bairdi Gill. (Species not well known.) 



Genus 2. — Petromyzon (Artedi) Linnaeus. 



§ Ichihyomyzon Girard. 



2. Petromyzon castaneus Girard. (Possibly two species : hirudo, castaneus, 



contained in the synonymy.) 



3. Petromyzon concolor Kirtland. 



§ Petromyzon. 



4. Petromyzon marinus L. 



Genus 3.— Ammocostes Dumeril. 



§ Entosphenus Gill. 



5. Ammoccetes tridentatus Gairdner. 



§ Ammoccetes. 



6. Ammoccetes aureus Bean. 



7. Ammoccetes cibarius Girard. 



8. Ammoccetes branchialis Linnaeus. (Possibly distinct from the European 



species, in which case a new name should be given to the American 

 form.) 



Indiana University, October 21, 1885. 



