INVERTEBRATE TAL^ONTOLOOV. 339 



possibly be tbe case with a few of his other species. A large majority of the 

 species included by him seem to be congeneric, however; and. as Mr. Conrad 

 in 18(>(), and Dr. Stoliczka in 1808, have proposed to retain the name Chem- 

 nitzia for shells more nearly of the latter type, I am inclined to adopt this 

 conclusion.* 



Many palaeontologists refer the Palaeozoic shells for which Phillips in 

 1841 proposed the name Loxonema, to Chemnitzia, and it is possible that this 

 may be correct, at least in part; that is, as Chemnitzia is here understood ; 

 but certainly not as first proposed by d'Orbigny in 1839. Others, again, 

 consider Turbonilla, Chemnitzia, and Loxonema as being all synonymous; 

 but in this view I cannot concur, for the reasons already explained. 



Whether the genus Chemnitzia is to be regarded as dating back to 

 Palaeozoic times depends entirely upon the limits assigned it. If the 

 numerous species referred to Loxonema are to be included, it would, of 

 course, extend far back into the Palasozoic rocks. I incline to the opinion, 

 however, that most, if not all, of the Palaeozoic species that have been 

 referred to this genus, ought to be separately arranged under Loxonema, 

 Michelia, and other groups. Some Triassic forms approah this genus, and 

 may possibly fall within it. In the Jurassic and Cretaceous rocks, it is cer- 

 tainly well developed ; and it seems not to have survived the close of the 

 Cretaceous period. 



If the group Loxonema is not distinct, as many think, from Chemnitzia 



as here understood, of course the former name will have to take precedence 



for the shells here in view, as d'Orbigny's name Chemnitzia, 1850, would be 



antedated ; for we cannot go back to d'Orbigny's original date, 1839, when the 



group then named by him is identical with the still older genus Turbonilla, 



Risso. 



Chemnitzia cerithif or mis, M. & H. (sp.). 



Plate 32, figs. 10, a, b. 



Scalarla cerithiformis, Meek and Hayden (1856), Proceed. Acad. Nat. Sci. Philad., VIII. 63 (not Watel., 1853). 



Turbonilla cerithiformis, Meek and Hayden (1860). ib., XII, 185. 



Scala (Acirsa) cerithiformis, Meek and Haydeu (1860), ib., 422.— Meek (1860), Smitheonian Check-List N. 



Am. Cret. Fossils, 20. 

 Sealaria MeeU, Nyst (1871), Ann. Soc. Malacologiqne de Belgique, VI, 44. 



Shell elongate-conical; spire turreted; volutions about eight, convex, 

 increasing rather gradually from the apex, last one rounded, and but little 



• The shells for which Mr. Conrad and Dr. Stoliczka retain the na::io Chemnitzia, have the body 

 volution and aperture more produced below than perhaps any of d'Orbigny's types; bul this is probably 

 not a generic distinction. 



