{287}_Cricotus_, with several species in Texas and Illinois. _C. heteroclitus_ was perhaps 10 feet long and probably aquatic. The skull has a long, narrow, depressed snout, the margins overhanging those of the lower jaw; its surface is encased in dermal bones, most of which still show sutures, so that for instance postfrontals, postorbitals, supratemporals and squamosals can be distinguished; all these are in contact with the long parietals and with the quadrato-jugal arch, covering the temporal region; but the supratemporals have a free projecting border, like the squamosals of the crocodiles. According to Cope's description the basioccipital is connected with the first vertebra by an undivided discoid "intercentrum," probably the true centrum, while the first basiventral mass, which would be, if independent, the first true intercentrum, is more probably connected with the first neural arch, thus constituting the ring of the atlas. The vertebrae are still temnospondylous, but no longer tripartite. The neural arch is fused with the interventralia into one mass, which carries the capitula and tubercula of the ribs, while the united basiventrals still remain as separate intercentral wedges. In the tail these wedges carry chevron-bones, and are enlarged into thick almost complete discs, or rather rings, while the whole vertebral column is still perforated, as also in _Eryops_, by the chorda dorsalis. The tail is long. The digits are devoid of claws. Remains of dermal armour exist on the throat in the shape of several large gular plates, while the whole belly is covered with many closely packed bony scales, which are arranged in chevron-shaped transverse rows.