_Cynognathus_, Karroo formation of South Africa. _C. crateronotus_ has a skull about 16 inches long, looking like that of a ferocious Carnivore; there are four incisors, huge canines, and nine molars, the latter with serrated edges and anterior and posterior cusps. The wide supratemporal fossa is bordered and closed behind by the broad lateral extension of the parietal, which joins a similar extension of the squamosal bone. The latter is very long, extending to the postfrontal and to a bone which, bordering the orbit posteriorly, is either an upward branch of the jugal, or a postorbital bone; the latter interpretation is made probable by the occurrence of a suture with the jugal in _C. platyceps_. The jugal bone is very long, beginning at the quadrate, running along the squamosal, and forming the lower border of the orbit. The number of vertebrae is large, there being as many as twenty-nine presacrals, six of which belong to the cervical region. {307}The atlas is fused with the axis; most of the thoracic ribs articulate partly upon the intercentra. The lumbar ribs are very peculiar; they are much expanded horizontally, and overlap each other, forming thereby intercostal foramina. The broad ilium is attached to three or four sacral ribs. The acetabulum is closed. The ventral side of the pelvis shows a broad symphysis and has a pair of obturator-foramina. The scapula is large, directed backwards, and shows a distinct, very Mammalian spine; it is fused with the coracoid and precoracoid. The occipital condyle of _C. platyceps_ is kidney-shaped, with the concavity directed upwards; in _C. berryi_ it is separated into two distinct knobs, the middle, basioccipital portion being apparently wanting. The mandible possesses a long coronoid process which ascends obliquely into the temporal fossa. _Aelurosaurus_, _Lycosaurus_, _Galesaurus_, and many others, likewise of the Karroo formation. In the first genus the splenial bones help to form the symphysis of the lower jaw; teeth are also found on the palate, in opposition to _Lycosaurus_. This has a skull 6 inches in length; the dental formula on either side is _i._ 4/3, _c._ 1/1, _m._ 5/5; the molars are slender, conical, and recurved. _Galesaurus_ seems to have been rather small, the low, triangular skull measuring only 2 to 3 inches in length, with four or five sharply pointed incisors, prominent canines and four or five small multicuspid or deeply serrated little molars.