Page:The Eurypterida of New York Volume 1.pdf/76

 Another more recent brief account is given by H. W. Fowler which reads in effect as follows:

The king crabs prefer such conditions as are afforded in Delaware Bay, where there are muddy or sandy bottoms, and it is seldom that they are found along the ocean beach. They also prefer more or less tranquil water where there is little or no surf and burrow in these places just under the sand or mud where they find an abundance of food in the many small animals; they are said to feed principally on worms. Although without any means of offense to such animals as fishes, they are amply protected from most enemies by their hard covering. The strong tail spine is used to right themselves when overturned. They progress through the sand by crawling, and when burying themselves are assisted by means of the hinged back, and also the spine. They are good swimmers, though they may frequently be seen crawling about over the bottom. When in shoal water they may easily be discovered by the two rows of small bubbles constantly appearing at the surface of the water.

From these notes on the habits of the American king crab it may be inferred that though a good swimmer, it mostly frequents the bottom and is a crawler, but feeds by digging in the mud and sand. In an aquarium such as that in Castle Garden, New York, it can be seen to swim easily by napping the powerful sternites which thus function as breathing and swimming organs. It crawls by the use of the four pairs of endognathites, and digs by the combined use of the shovelshaped head shield, the pushing spine, the activity of the legs, especially of the last pair, which are adapted to this function and probably even by the aid of the flapping sternites.

The features of Limulus which appear to be of importance in ascertaining the habits of the eurypterids, being also observed in one or the other of their genera, are: the broad carapace, its beveled edge, the triangular concave shield in the middle of the doublure of the underside, the subapical position of the lateral eyes, the large, platelike sternites,