656 DICRAN0ZYGOMA LEPT0SCELUS. [A-Ug. I9OO, 



appears to curve in a straight bow, and bend a little backward. 

 The external surface of the shaft is flattened proximally, and marked 

 with faint longitudinal lines ; the narrow middle part, scarcely more 

 than I inch wide, is well rounded, with an appearance of a small 

 longitudinal muscular attachment, below which the bone is flattened 

 towards the distal end, which appears to be thinner than the 

 proximal end, and twisted a little backward. It may be compared 

 with the fibula of Tribolodon. 



There is no trace of any bone of the tarsus or hind-foot, nor is 

 there any trace of armour. 



These remains indicate an animal about 2 feet long, exclusive 

 of the tail, standing probably about 8 inches high, not more than 

 6 inches wide in the fore part of the body, or more than 4 inches 

 wide in the pelvic region. It must have been an animal of great 

 mobility, capable of easily bending the body ; and by straightening 

 the limbs, of occasionally raising its height to 10 inches or more. 



Notwithstanding the imperfection of the skull, it may be regarded, 

 from the structure of the head, pelvis, and femur, as a new type 

 of Theriodont reptile, as contributing important facts to the 

 osteology of the group, more especially in regard to the natural 

 association of the bones. 



It is possibly to be included in the Cynodontia, from which it 

 differs in characters of the ilium, scapula, and skull, which may 

 be more than generic differences ; but I have some slight ground, 

 from] fragments picked up on the drift-trail, for suspecting that in 

 Cynognathus the tibia and fibula are less unequal in size than they 

 are known to be in Alicrogomphodon and in Eurycarpus (which is 

 possibly Lycosaurian). The determination of the exact systematic 

 position of the genus within the Theriodontia, depends upon such 

 evidence as may be obtainable from the missing slab already 

 mentioned, which is reputed to contain the remainder of the skull. 



I am indebted to the Government Grant Committee of the Royal 

 Society, 1889, for the opportunity of examining this specimen in 

 Grahamstown ; and to the Trustees and Officers of the Albany 

 Museum and the British Museum (Natural History) for facilities in 

 making this record of its structures. 



EXPLANATION OF PLATE XXXVI. 



Photographic reproduction of the cast of a skeleton of Dicranozygoma 

 leptoscelus, gen. et sp. nov. ^ nat. size. 



o — Orbits. 



p = Parietal foramen. 



f,-m = Foramen magnum. 



sq = Squamosal bone. 



c.v = Displaced cervical vertebrae. 

 , d.r = Dorsal vertebras and ribs. 



l.v = Lumbar vertebrae and ribs. 



II = Iliac bones. 



i.p = Ischiac process of ilium. 



Is = Ischium. 



F = Femur. 



/= Fibula. 



t = Tibia. 



Se = Scapula. 



H = Humerus. 

 c.p = Claw-pbalange. 



Discussion. 

 Prof. Sollas and Mr. Lydekker spoke, and the Author replied. 



