MUSEUM OF COMPARATIVE ZOOLOGY. 101 



Etoupe Fours, Thouars, Pres de Semur, Vassy in Yonne, Amayer sur Orne, 

 Boll, and Metzingen ; Coll. L. de Koninck, Dr. Krantz, M. Boucault, Prof. 

 Bronn, Duval, and Damon. 



Leioceras* Hyatt. 



Abdomen keeled, acute. Sides of the whorls flattened. Envelopment 

 uniformly greater than in Grammoceras. The young differ, however, in 

 being much flatter at the corresponding periods of growth. The lobes and 

 cells, also, are less obtuse, shallower, and much more numerous. 



Leioceras lythense Hyatt. 



Amm. lythensis Young and Bird, Phil. Geol. York., p. 164, pi. 13, fig. 6. 

 Loc. Whitby ; Coll. Prof. Bronn. 



Leioceras opalinum Hyatt. 



Naut. opalinus Rein., Naut. et Argo., p. 55, pi. 1, fig. 1. 



Naul. comptus Rein., Naut. et Argo., p. 57, pi. 1, figs. 5, 6. 



Amm. primordial!* Schlot., Pet., No. 7, p. G7. 



Amm. erralus Young and Bird, Phil. Geol. York., pi. 13, fig. 7. 



Amm. primoriliulis Ziet., Verst. Wiirt., p. 5, pi. 4, fig. 4. 



Amm. primord talis D'Orb., Terr. Jurass., Ceph., p. 235, pi. G2. 



Amm. opalinus Quens'dt, Die Ceph., p. 115, pi. 7, fig. 10. 



Loc. Robin Hood's Bay, Whitby, Trocester Hill, La Verpilliere in Am, 

 St. Quentin pies Verpillier, Szaflary, Amberg pres de Goslar, NeufTen, 

 Quedlinburg, Teufelsloch, Gundershofen, and Metzingen ; Coll. Mus. of 

 Stuttgart, Dr. Krantz, Prof. Bronn, L. Agassiz, and M. Boucault. 



Leioceras elegans Hyatt. 



Amm. elegans Sow., Min. Conch., v. 1, p. 213, pi. 94, fig. 1. 

 Loc. Whitby; Coll. Dr. Kiantz. 



Leioceras complanatum Hyatt. 



Amm. complanalus Brug., Encycl., p. 38, No. 11. 



Amm. mulgracius Young and Bird, Phil. Geol. York., p. 251, pi. 13, fig. 8- 



Amm. elegans Phil. Geol. York., pi. 13, fig. 2. 



Amm. c/r</a>i* Ziet., Verst. Wiirt., p. 22, pi. 16, fig. 5. 



Amm. cum plana! us D'Orb, Terr. Jurass., p. 353, pi. 114. 



Loc. Whitby, Lyme Regis, Villebois in Ain, Mussy pres de Semur, Aval- 

 Ion, Privas, Boll, and Ubstadt bei Bruchsal ; Coll. Prof. Bronn, Dr. Krantz, 

 M. Boucault, and Damon. 



* Afior, smooth. 



