SYSTEMATIC REVISION 8 1 



Table III — Continued. 

 V. Trematopsida: 



1. Small, not over 500 centimeters long, head disproportionately large. 



2. Occipital condyles separate. 



3. Otic notch small, completely inclosed, forming a fenestra. 



4. Parasphenoid vestigial, or absent. 



5. One (?) functional sacral rib. 



6. No armor on back. 



7. Clavicles and interclavicle without external sculpture. 



8. Cleithrum probably present, unknown. 



9. Probably as in Eryops. 



10. Femur with prominent ridge on the posterior surface, 



11. The two halves of the neural spine united. 



12. Intercentra thick constricting the notochordal space. No processes on the 



intercentra for the ribs. 



Table IF. Showing the Characters of the Embolomerous Cricotida. 



1. Skull elongate, resembling that of Archegosaurus. 



2. Nares not terminal, near outer edge of skull. 



3. Orbits near middle of skull, looking upward and outward. 



4. Intercentra complete, perforated disks, forming with the equally developed 



pleurocentra, embolomerous vertebrae. 



5. Two (.'') sacral vertebrae, the anterior one with a large rib. 



6. Caudal vertebrae numerous. Chevrons coossified with intercentra. 



7. Ilium reptilian, with a strong projection to the rear. 



8. A close abdominal armor of imbricate scales, arranged in a chevron pattern. 



Eryops: 



Table V. Contrasting the Characters of the Genera of the Family Eryopida, 



1. Large. From 2 to 2.5 meters in length. 



2. Otic notch present. 



3. Orbits proportionately small, a little posterior to the middle of the skull. 



4. Nares some distance from the lateral and anterior edges. 



5. Angle of lower jaw not produced beyond the quadrate. 



6. Lower jaw wide vertically. 



7. Skull covered with a coarse sculpture, especially strong on posterior portion. 



8. Teeth irregular in size. Large tusks, in pairs, on prevomers, palatines, and 



maxillaries. 



9. Dentine simply but strongly infolded. 



10. Fine teeth on prevomers, pterygoids, and parasphenoids. 



11. Ribs expanded, with an angular extension of the posterior edge. 



12. A single sacral rib. 



13. Pelvis narrow, with a long and narrow symphysis, 



14. Spines of dorsal vertebrae with rugose apices. 



15. Spines of caudal vertebrae bifurcate. 



16. Humerus short with powerful processes; proximal and distal extremities at 



right angles. 



17. Femur with narrow and high ridge on posterior face. 



18. Feet short and wide. 



Parioxys: 



1. Small, not over 500 centimeters in length. 



2. Otic notch present. 



3. Orbits proportionately large, in posterior half of skull. 



4. Nares more nearly terminal than in Eryops. 



5. Angle of jaw continued behind the quadrate. 



6. Lower jaw narrower, vertically, than in Eryops. 



7. Only the skull known. 



Anisodexis: 



The specimen is fragmentary and can not be directly compared with the other 

 members of the family. 



