CRUSTACEA. / 



the freshwater limestone of (Eningen and Locle. These arc 

 small animals with bivalved kidney-shaped shells, very like spe- 

 cies which still live in the Swiss fresh waters, where they swim 

 about by the action of their antennse, which are fringed with 

 long hairs, and of their fore legs, which project beyond the 

 shells. They serve as the food of a great number of aquatic 

 insects. 



The Gammaridse are represented at (Eningen by a species 

 (Gammarus oeningensis, Heer, fig. 209) very like the common 

 Grammarus pulex, Deg., sp., of the Swiss lakes and rivers. The 

 existence of water-fleas (Daphniae) is shown at least by their 

 eggs, which have been found at CEningen (fig. 206). The 

 Daphnia have two kinds of eggs summer eggs, which have no 

 peculiar envelope, and winter eggs, a pair of which are placed in 

 a small shallow receptacle called the ephippium (saddle). The 

 ephippia found at CEningen form small oval scales, in which the 

 two eggs may be clearly recognized. They are consequently 

 winter eggs, like those which may be met with in the Swiss 

 waters from autumn to spring. 



The largest and most important animals of this class are the 

 Decapods, fragments of which are found here and there in the 

 freshwater Miocene. In most places (as at Schwamendingen), 

 however, they are so imperfect that we cannot determine them. 

 CEningen, again, gives us some definite information about them. 

 The three species occurring there belong, curiously enough, to 

 the Prawns and Crabs, which, with very few exceptions, are in- 

 habitants of the sea, whilst the Lake of CEningen undoubtedly 

 contained fresh water, as is proved by the numerous freshwater 

 animals of other kinds which have been found in its deposits. 

 The (Eningian prawns constitute a peculiar and extinct genus 

 (Homely s, Myr.), the sole species of which (H. major, Myr.) is 

 distinguished by its extremely delicate long antennae and its 

 smooth pectoral spine. It is a little smaller than the common 

 prawn (Palcemon squilla, Linn.), and is very like the freshwater 

 prawn (P. fluviatilis, Mart.), nearly allied to the common prawn, 

 and living in the Lago di Garda as well as in the fresh waters 

 of Parma. Homely s major occurs only in the insect-bed of the 

 lower quarry at CEningen. The Crabs are found almost exclu- 

 sively in the ' ' Kesselstein " of the upper quarry. There are 



