Sea Scorpion Notebook

Pterygotus was the largest of the eurypterids, the 'sea scorpions', and could grow as large as an adult human being. They had good eyes and large pincers, and perhaps explain why the ancestors of millipedes and spiders apparently found life much more congenial on land at about this time. The image is taken from a mid-century encyclopædia, with charmingly eccentric captions.