y2 REVISION OF THE PELYCOSAURIA. 



Table II.— Contrasting the Families of the Pelvcosauria— Continued. 



II. Clefsydropidce — Continued. 

 Subfamilies. 



I. ClepsydropincE. 



1. Vertebral spines simple. 



2. The bottom line of the anterior dorsal and posterior lumbar vertebra greatly shortened. 



3. Cervicals larger than anterior dorsals. 



4. Crest of the ilium prolonged to the rear. 



5. Dorsal ribs with tuberculum attached to prominent transverse process. 



II. Naosaurince. 



1. Vertebral spines with lateral processes. 



2. Bottom line of anterior and posterior dorsal and posterior lumbar vertebrae not greatly shortened. 



3. Cervicals smaller than anterior dorsal. 



4. Crest of the ilium vertical and expanded. 



5. Dorsal vertebrae with tuberculum reduced to a tuberosity on the edge of the rib. 

 III. Edafhosaia-idcE. (Possibly founded on a skull of Naosaurtis.) 



1. Skull acuminate, flat. Higher posteriorly. 



2. Tooth line straight. 



3. Neural spines (probably) low. 



4. Character not shown. 



Table III.— Contrasting the Characters of the Genera of the Poliosaurid.^. 



I. Poliosaitriis. 



1. No diastemal notch between maxillary and premaxillary. The series of teeth uninterrupted. 



2. No well-defined canine in the maxillary ; several maxillary teeth in the anterior third larger than the 



others. Incisor teeth enlarged. 



3. Teeth with faint anterior and posterior cutting edges ; not crenate. 



4. Neural arches of the vertebra; free from the centrum through life. 



5. Only slight difference in the length of the bottom line of the vertebrae in different parts of the column. 



6. Anterior dorsals with wide face for the intercentrum on the lower edge of the anterior face of the centrum; 



without sharp and deep median keel. Posterior lumbars not greatly shortened and without wide exten- 

 sion of the inferior edges of the faces of the centra. 



7. Neural spines short. 



8. Spine of the axis low and broad. 



g. Limb bones without well-developed articular faces. 



10. Character not shown. 



11. Abdominal scutes present. 



12. Tail long. 



13. A small, probably aquatic animal, not exceeding 700 mm. in length. 



II. Varanosaiirus. (Ribs with rudimentary capitulum.) 



1. No diastemal notch between maxillary and premaxillary. 



2. Two enlarged canines in maxillary. Incisor teeth enlarged. 



3. Character not shown. 



4. Neural arch of vertebrae coossified with centra in adult. 



5. Only a slight difference in the length of the bottom line of the vertebrae in different parts of the column. 



Anterior dorsals with wide face on the anterior edge for the intercentrum. 



6. Character not shown. 



7. Spines short. 



8. Spine of the axis low and broad. 



9. Limb bones without well-developed articular faces. 



10. Character not shown. 



11. Abdominal scutes present. 



12. Tail long. 



13. 600 to 800 mm. long. 



