SCORPIONS AND THEIR ANTIQUITY 371 
its maximum development, the largest forms being, I 
believe, South American and South African. 
In existing kinds of scorpions the median dorsal eye- 
tubercles are, as a rule, far removed from the front margin 
of the cephalo-thorax, and thus placed behind the lateral 
eyes. Apparently the only fossil scorpions agreeing with 
this group that have been hitherto discovered occur pre- 
served in amber of late Tertiary age; scorpions being quite 
unknown in lower Tertiary or Secondary rocks. Needless 
to say that this is not owing to their non-existence in those 
epochs, but is due either to such rocks being unsuited to the 
preservation of their remains, or having been deposited far 
out to sea. 
When, however, we reach the Palaeozoic coal-measures, 
which are mainly of fresh-water origin, and, therefore, just 
where we should expect to find such creatures, remains of 
scorpions have been met with both in Europe and North 
America, some of the species attaining very considerable 
dimensions. Both in these Carboniferous scorpions and 
also in certain still older ones from the Silurian rocks, the 
eye-tubercles are placed either on the actual front margin 
of the cephalo-thorax, or only a short distance behind it; 
and they are thus regarded as forming a group apart from 
the modern scorpions. In the Carboniferous genus C/ythoph- 
thalmus, the median eye-tubercles are immense, and occupy 
almost the entire front half of the cephalo-thorax ; the lateral 
eyes forming a semicircle behind and to the sides of the 
larger ones. The maxillary palpi form pincers proportion- 
ately as large as in the modern forms, while the legs have 
similar double claws. The genus Loscorpius, which is 
likewise common to the Carboniferous rocks of both halves 
of the northern hemispheres, has all the general features 
of the preceding, with the exception that the arrangement 
