BRONN ON PAL^ONTOLOGICAL STATICS. 53 



of which the conehyUse again are almost entirely terrestrial species, 

 which are distinct from the former*. 



u. The miocene marine remains which Michelottif has recently 

 described are procured from a thick mass of grey marls round Turin, 

 Asti and Tortona, but which also occurs in the Piacentine country 

 near Basedasco ; yet, notwithstanding this very considerable extent, 

 it only corresponds at most to one of our * lives of a species,' as it 

 must be placed on the parallel of u, or perhaps only of its upper 

 portion. During its deposition no considerable change of conditions 

 has taken place. Its fauna contains — 



Genera. Species. 



Rhizopoda (Foraminifera) .... 8 19 



Pol}^i 33 103 



Echinoderms 8 23 



Crustacea 1 1 > 1 71 : 740 



Cirripedes 3 6 



Annelids 1 1 



Conchylise 117 587_^ 



Conchyliae, Cirripedes. 

 But now there has been enumerated by Genera. Species. Species. 



De Gerville for the coasts of the Manche loo ^on n 

 1 , , n > 28 180 9 



departments only J 



Vernay at Nice, not quite 100 250 9 



Philippi for the Sicilian-Calabrian coasts .... — 545 18 



(both with the exclusion of naked and non-marine conchyliae) ; 

 hence the Tortona beds, even in respect to the Cirripeds, of which many 

 are very friable or entirely without shells, have much the advantage, 

 u. For the middle-tertiary freshwater beds we select the two very 

 limited localities, situated quite close to each other, of Wiesbaden 

 and Hochheim, which, although they have not many species in com- 

 mon, yet assuredly do not fill up an entire 'life of a species' as we 

 have above defined it. From these Thoma has described Helix with 

 32 species, and 12 other genera of non-marine conchyliae with 23 

 species, or together 13 genera with 55 species of land and freshwater 

 conchyliae. According to Al. Braun, Hochheim furnishes 57 and 

 Wiesbaden 22 species alone of land-shells, which together, as only 8 

 species are common, make 71 species. The entire miocene basin of 

 Mayence, according to him, produces 74 species of land and 28 spe- 

 cies of brackish and freshwater conchyliae, together 1 02 species from 

 20 genera, or as many as we are now able to find living in this basin ; 

 tor m it, jjj ^^g Miocene time. At present. 



Species. Species. 



Helix has produced 41 32 



Bulimus 10 4 



Pupa 16 14 



Littorinella 9 1 &c. 



* Jahrbuch, 1845, p. 738 ; 1848, p. 637. 



t In the Naturkund. Verhandl. van de Maatscli. te Harlem 1847, b. iii, ii. 

 pp. 1-408. 



