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 Clythoph- 

 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 Eoscorpius, 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 



