Geological Society of London. 283 
regarded by the author as the anterior bone of the sternum proper, 
which is usually unossified in recent lizards, but well ossified in 
Ornithorhynchus. In the scapula also the author pointed out re- 
semblances to that bone in Ornithorhynchus. The humerus in its 
general porportions, and especially in the great development of its 
ridges, was also shown to resemble the same bone in the Mono- 
tremes. The ungual phalanges were described as broad and obtuse, 
probably constructed to bear claws adapted for digging, as in 
Echidna; the femur also resembles that of the last-named animal. 
The author remarked upon these approximations to the Mono- 
trematous Mammalia, in allusion to which he proposed the name of 
Platypodosaurus robustus for this animal, the humerus of which 
was 103 inches long and nearly 6 inches broad at the distal end. 
He also alluded to the interesting problems opened up by the study 
of these South-African reptiles in connexion with their possible 
relationships to the low implacental Mammalia of New Guinea, 
Australia, and Tasmania. 
2. “Note on the Occurrence of a New Species of Iguanodon in the 
Kimmeridge Clay at Cumnor Hurst, three miles west of Oxford.” 
By Prof. J. Prestwich, M.A., F.R.S., F.G.S. 
The pit in which the occurrence of Iguanodon was discovered was 
worked in Kimmeridge Clay at the foot of an outlying mass of 
Lower Greensand forming an isolated hill. The Portland beds, 
which occur at Shotover, are here wanting. The bones were found 
in a thin sandy seam intercalated in the clay, and traversing the 
hill at least 15 feet below the Greensand. The skeleton was 
probably almost entire; but, as attention was not directed to it 
until nearly all the clay had been removed, many bones were lost and 
others injured. Several vertebra of Ichthyosaurus were found in 
the same seam, and the characteristic Gryphea virgula occurred in 
profusion. The clay above and below contained fossils of Kim- 
meridge types. The author stated his opinion that land probably 
lay to the south-west of the Oxford district. 
3. “On Iguanodon Prestwichii, a New Species from the Kimme- 
ridge Clay.” By J. W. Hulke, Hsq., F.R.S., F.G.S. 
In this paper the author described in detail the remains of Igua- 
nodon found at Cumnor Hurst in the Kimmeridge Clay, as described 
in the preceding paper. They illustrated nearly every part of the 
skeleton of an immature individual, adding greatly to our knowledge 
of the variation of the vertebre in the several regions of the verte- 
bral column, and of the structure of the head and hind limbs. In 
the latter, both the tibia and the fibula articulate (as in embryo birds) 
with the os calcis, which bone is now first identified in Igquanodon. 
The sacral vertebrae were only four in number, and the species 
further differed from the Wealden Iguanodon Mantelli in the simpler 
character of the serration of the teeth, of which the lamelle are not 
mammillated, and in having the vertebre of the trunk and sacrum not 
so compressed. The author named the species Iguanodon Prestwichii. 
