80 BULLETIN OF THE 



widely divergent, the series between the two forms showed them to be ono 

 species with only local differences. 



Asteroceras stellare Hyatt. 



Amm. stellaris Sow., Min. Conch., v. 1, p. 211, pi. 93. 



A mm. Turneri Sow., Min. Conch., v. 5, p. 75, pi. 452. 



Amm. stellaris Haucr, Ceph. d. Lias d. Nordo.itlichen Alpen, p. 22, pi. 5, 

 figs. 1, 2. 



Loc. Lyme Regis, Gloucester, and Scmur ; Coll. B. M. Wright, Har- 

 der, Dr. Krantz, and M. Boucault. 



Asteroceras Collenotii Hyatt. 



Amm. Collenotii D'Orb., Terr. Jurass., 1, p. 305, pi. 95. 

 Loc. England and Semur ; Coll. Marder and M. Boucault. 



LIPAROCERATIDJE Hyatt. 



Microceras* Hyatt. 



Abdomen flattened ; sides rounded or flattened. The pilae in the adult 

 are undivided upon the abdomen, and are continuous with the large, single 

 lateral pila?, which last may be ornamented with either one or two rows of 

 small tubercles, or be bare. 



The envelopment only covers the abdomen of each internal whorl, reach- 

 ing no farther than the first row of tubercles, umbilicus is consecpuently ex- 

 posed in all the species. The increase of the radii is slow, the species have 

 a greater number of whorls than in succeeding genera, and are also of 

 smaller size. The septa are remarkable for their unequally divided lobes 

 and cells, the large size of the abdominal lobe, the insignificant size of the 

 two lateral lobes, especially the inf. lateral, and the great breadth of the 

 cells. 



Microceras biferum Hyatt. 



Anon, bifer bispinosus Quens'dt, Der Jura, p. 101, pi. 13, figs. 10, 11, 

 and 13. 



Amm. bifer nudicosta Quens'dt, Der Jura, p. 104, pi. 13, fig. 14. 



Loc. Gloucester, Pleinsbach, Balingen, Boll ; Coll. L. de. Koninck, Dr. 

 Krantz, Mus. of Stuttgart. 



Microceras confusum Hyatt. 



Amm. confusus Quens'dt, Der Jura, p. 12/, pi. 75, figs. 8, 9. 

 Loc. Lansdown Station, near Cheltenham, and Gloucester ; Coll. L. de 

 Koninck. 



* blinpos, small. 



