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ON THE FAUNA AND FLORA OF THR TRIAS OF THR BRITISH ISLES. 153 
Since the four forms just referred to were first described another 
form, A 4, has been found varying in a different way from A 1, which 
otherwise it strongly resembles ; the LY. toe in A 4 is relatively shorter, 
and generally carries a longer and more powerful nail than do the other 
toes. Accompanying this feature is a very different print of the manus; 
in A 1 and 2 the manus is about half the size of the pes and has five 
widely spread digits and forms a short broad print. In A 4 the print 
of the manus is very much smaller, has four very short broad digits, 
with occasionally a very uncertain trace of a fifth. A 4, however, 
resembles A 1 in having the skin of both pes and manus covered with 
small tubercles. A 4 has been found in series on the same slab with 
prints of Al. It has so far only been found at Storeton, but on slabs 
raised there at intervals of several years. 
Nothing has been found to indicate that these variations in form 
have been caused by difference in the material in which the first im- 
pressions were made; in fact, this is disproved by the different forms 
having been found in close proximity to each other on a perfectly uniform 
surface. Neither is there any indication of their occurring on different 
horizons. 
It may be worth noting that the forms A 1 to 4 are seldom, if ever, 
found at Runcorn, whilst they are common a few miles east and west, and 
that whilst A 2 is common on Lymm and Warrington slabs, it is rather 
rare at Storeton. The beds at each place are about the same age, although 
it seems difficult to correlate them with each other. There would seem 
to be little probability of a continuation of the same bed for any great 
distance if, as is now generally held to be the case, the beds represent the 
bottoms of isolated, somewhat temporary, pools or lagoons. 
It should also be borne in mind that no large extent of the surface of 
the footprint beds is exposed in quarries in the course of several years, 
and the prints of one or two species that happened to go to the water 
together have been seen, whilst the prints of other species may be hidden 
from us a few yards off on exactly the same horizon. 
The two small prints B 1 and 2 have not been recognised in any new 
material, neither has the small print ‘ L,’ which, though much smaller, 
resembles the pes of A except that there is no trace of the first or inner 
toe. The manus resembles that of A 4, but in the very few examples we 
have, only three digits areseen. The only example of this print in series 
is in the British Museum (Natural History) from Storeton, whence it 
must have been obtained some sixty years ago. A single print of the pes 
was found at Storeton a few years since, and another came from Guy’s 
Cliff, Warwick, so they cannot be the tracks of one abnormal individual. 
The Rhynchosauroid prints have five toes, little or no palmar surface, 
_ and the fourth toe the longest. -To this group belong D 1 to 7 and E. 
D 1 seems to be the most common form, and to approach nearest to 
what might be expected from Rhynchosaurus articeps. D2 is much like 
it, but the toes are narrower and not so generally curved. It is very 
seldom that in either form there is any trace of the impression of a web. 
A webbed foot would leave some trace of the web in all but very 
exceptional instances. However, on a slab in the British Museum 
(B 295) there is what appears to be a distinct web, and, as pointed out by 
Mr. D. G. S. Watson, there is another in the Manchester Museum.! In 
* Mr. Watson’s paper, ‘Some Reptilian Tracks from the Trias of Runcorn,’ pre- 
sented at the June meeting of the Geological Society, not yet printed. 
