129 



NoETLiNG M has divided the species ofCoeloma into two groups: 

 La eve s and Tuber cul at i. To the first group are referred 

 the forms whose carapace is almost perfectly smooth with the 

 exception of a few rather large nodes. To the second group 

 belong those whose carapace is more uneven, and provided 

 with rather large nodes and tubercles. To the Laeves he refers 

 Coeloma vigil Milne Edwards from the Vicention Eocene, 

 С balticum Schlüter from the Lower Oligocène formation in 

 Samland, С. granulosum Milne Edwards from the Upper Nummu- 

 litic beds near Biarritz, and C. Beidemeisteri Noetling from the 

 Phosphate-beds near Büddenstedt and Helmstedt. Of the second 

 group, Tuberculati, he knows only two species, viz. C. tauni- 

 cum V. Meyer S2:). from the Middle Oligocène Septarian clay 

 near Breckenheira, and C. Cred?ieri v. Schloth. sp. from the 

 Upper Oligocène in the neighbourhood of Hildesheim. To 

 these Stolley^) adds two more species, viz. C. rupeliense St aimer 

 from the Middle Oligocène Rupel clay near Rupelmonde in 

 Belgium, and C. holsaticum Stolley from the Middle Oligocène 

 Septarian clay near Itzehoe in Holstein. 



According to Noetling the group Laeves contains chiefly 

 earlier species, while the group Tuberculati is characteristic of 

 the younger Eogene. 



Coeloma bicarinatum n. sp. is quite in agreement with the 

 group Laeves^ and if, as Noetling thinks, in the development 

 from the older to the younger species there is an inclination 

 towards a sharper definition of the furrows, and a richer 

 ornamentation of the surface, it must certainly be one of the 

 oldest species. Especially characteristic of this species, and very 



') F. Noetling: Die Fauna des samländischen Tertiärs. I Theil. — Ab- 



handl. zur geol. Specialkarte von Preussen und den Thüringsch. Staaten. 



Bd. 6, Heft. 3. Berlin 1885. S. 415—17. 

 ^) E. Stolley: Ueber zwei Brachyuren aus dem mitteloligocänen Septarien- 



thon Norddeutschlands. — Mitth. aus. dem mineralog. Institut der Univ. 



Kiel. Bd. I, Heft. 3. Kiel 1890. S. 165. 

 XXIX. 9 



