120 MOLLUSC A. 



No. 482. Ammonites cordatus, Sow. 



This, a young shell, shows the cordate keel from which 

 the specific term is derived, and which assigns the species 

 to the group "AmaltJiei." From the Oxford Clay (Middle 

 Oolite), and now in the Ward Museum, University of Ro- 

 chester. Price, $0.25. 



No. 483. Ammonites cordatus, Sow. 



This is the internal cast of an unusually large specimen of this interesting 

 species. It shows the spherical character of the very old form, and the great 

 size of the last chamber. From the Middle Oolite of France. 



Diameter, 11. Price, £2.00. 



No. 484. Ammonites cordatus, Sow. 



Internal cast of the adult shell showing the foliations. From 

 the Oxford Clay (Middle Oolite), Calvados, France, and now in the 

 Ward Museum, University of Eochester. Diameter, 7 Price, $0.80. 



No. 485. Ammonites cordatus, Sow. 



From the same locality as the preceding, and now in the private Geological 

 Cabinet of Mr. Ward, Rochester. Price, $0.75. 



No. 486. Ammonites coronatus, Brug. 



This species from the Middle Oolite, very much resembles A. gigas, Ziet. of 

 the Upper Oolite. It is the type of Von Buch's group, "Cwonati." From Villere, 

 France, and now in the Ward Museum, University of Rochester. Price, $1.00. 



No. 487. Ammonites coronatus, Brug. 



Younger Shell. From the same locality and Museum as the preceding. 



Price, $0.50. 



No. 488. Ammonites comucopise, D'Orb. 



This elegant Ammonite very closely resembles A, firribriatus, Sow., but is 

 considered by D'Orbigny a distinct species. Its several whorls are coiled quite 

 loosely and taper very rapidly towards the centre of the shell. From the Upper 

 Lias, Verpilliere, France, and now in the Ward Museum, University of Roches- 

 ter. Diameter, 12. Price, $2.50. 



No. 483. Ammonites crassus, Phil. 



This is one of the forms closely allied to the A. communis, from which it 

 appears to differ chiefly in its greater thickness. Like the latter, it is very fre" 

 quently found forming the central nucleus of discoid concretions of slaty lime- 

 stone. These concretions owe their origin to the attracting and cementing power 

 of the decomposing mollusc. From the Upper Lias, Whitby, England, and now 

 in the Ward Museum, University of Rochester. Price, $0.40. 



