77° Marvels of the Universe 
have been propelled by undulating 
movements of the long and im- 
mensely powerful tail. The fore- 
limbs, on such occasions, would 
serve rather as balances. The great 
hind limbs, like those of all the 
bipedal reptiles, were bird-like, and 
bore but three toes. 
But the most remarkable feature 
of this strange beast was its head. 
All the later Dinosaurs displayed a 
tendency to lose their teeth, replacing 
them with horny plates forming a 
beak. In the Duck-billed Dragon 
this new-fangled notion of suppress- 
ing the teeth was associated with 
a successful attempt to break the 
record in the matter of teeth borne 
on the jaws at the back part of the 
mouth, answering to the “ grinders ”’ 
or “cheek” teeth. For here they 
existed in row upon row one above 
the other, small, spear-shaped, and 
tightly wedged together like a pave- 
ment ; over two thousand belonged 
to the upper jaw alone. But, it 
must be remembered, they were not 
all in use at once ; only those along 
the cutting edge of the jaws were 
co mois Ono Hind of ont exci on Gitar mere Uo Ginciaro amino and  muincHOMA, AS Wnese ZOE WO, OF 
bores through the base to the other spine. Another ant makes an entrance at broken, they were shed, and replaced 
the base leading to both spines. : 9 . 
by those in the row immediately 
below. Thus an almost endless succession of teeth was possible. These teeth were admirably 
adapted to cutting up grass and rushes and submerged weeds, which were evidently seized by the 
curious, toothless, shovel-like ‘‘ beak ’’ which formed the fore-part of the jaws. 
BULL’S-HORN ACACIA. 
The interior of these spines is used as food by the ants that adopt them 
ANTS AND THE BULL’S-HORN ACACIA 
BY EDWARD STEP, F.L.S. 
To the average person of intelligence the animal world is separated from the plant world by a great 
and unbridgable gulf. Animals of many kinds, including man, feed upon plants. Man admires 
the flowers of plants, and occasionally shows an interest in the structure and development of plants ; 
but though he may have read of the remarkable behaviour of insectivorous plants and the inter- 
relations between flowers and pollinating insects, he is too apt to regard these things as mere fairy tales, 
invented by the naturalist to amuse him. On the whole, his view of the nature of plants remains 
pretty much what it was a hundred years ago ; and to those who have no actual intimate acquaint- 
ance with the plant as a living thing, it is probably easy to hold such a view. But it is difficult 
for those who have studied the plants, not as dead and dry herbarium specimens, but as they carry 
out their natural functions in the woods and fields. There are so many points at which certain 
