576 MANUAL OF NATURAL HISTORY. 



Perdix; the grallatorial genera of Tantalus, Scolo- 

 pax, and Numenius, and the natatorial Carbo, or 

 Cormorant. In the eocene of Sheppey, an extinct 

 raptorial bird, allied to the vultures (Lithornis), 

 and another departed form allied to the King- 

 fishers (Haley omis) have been discovered ; and in 

 the schists of Glarus, an extinct genus of incessorial 

 birds, the Pyctomis. Among reptilian forms, nearly- 

 perfect carapaces of turtles and tortoises have been 

 found in the eocene strata of Hampshire and the 

 Isle of Wight ; an extinct genus of serpents, Palce- 

 ophis, has been discovered in the sand of Kyson, 

 together with species of the fresh-water tortoises, 

 Emys and Platemys. The fishes of this group com- 

 prise seven extinct genera of Placoids, belonging to 

 the family of Chimceridce; a single fossil Diodon ; 

 and several genera, mostly extinct, of the Ostra- 

 ciontidce. In Mollusca, extinct species of existing 

 genera are very numerous in the marine deposits of 

 the tertiary strata ; two hundred and twenty fossil 

 species of Cerithium alone having been identified, 

 besides numbers of Pleurotomia, Fusus, and Buc- 

 cinum. A few extinct genera also occur, as Pile- 

 olus, Omalaxis, and Pleurotomaria. But few spe- 

 cies of Helicidw have been found ; only ten species 

 of Patella ; one Haliotis ; about seventeen Neri- 

 tince; numerous Trochidce; nineteen Cowries;' and 

 many species of cones, helmet-shells, rock-shells, and 

 tritons. Among Pteropods, a few extinct forms 

 occur , two fossil species of Gavolina are found in 

 the tertiary beds of Dax and Turin. Nearly a 



