18 AMERICAN JOURNAL 



Margaritifera, Malleus, Aucella, Etimicrotis, (n. g.,) 



and probably the extinct genera, 

 Monotis, Halohia, Pteronites, Posidonomya, 



Me LINING, {Ferna or Isognomon group.) 

 Genera Crenaiula, Melinar= Perna, (Brug., 



not Adanson,) Bakevellia, Gervillia, 



Inoceramus, Pulvinites. 



Notice of a small collection of Fossih f7-om the Potsdam 

 Sandstone of Wisconsin, and Lake Superior Sandstone 

 of Michigan: by prof. Alexander winchell. 



The new shells are: — 



Orthis Barabuensis. 



Straparollus 'prim or di alls. 



Pleurotomaria advena. 



No. Ill, May, 1864. 



On the Cretaceous and Superior Formations of West Ten- 

 nessee : BY J. M. SAFFORD. 



Lists of species of shells ocouring in the various formations 

 are given, and the following recent species are mentioned as 

 occuring fossil in the Bluff Loam, (Post-Tertiarj.) 



Helices apj^ressa, hirsnta, monodon, solitaria profunda; Pla- 

 norhis hicarinatus, Amnicola lapidaria, and species of Lymnea, 

 and Cyclas. 



No. 112, May, 1864. 



On the structural characters of the so-called Melanians of 

 North America, by wm. stimpson, m. d. 



A most excellent paper, containing a detailed account of the 

 results of anatomical investigations of the soft parts of 

 Anculosa dissimilis and Goniohasis Yirginica. Dr. Stimpson 

 also examined lo. fiuvialis, but does not find anj^ structural 

 differences in either of these species to warrant the separa- 

 tion of the Melanians into genera ; at the same time he agrees 

 with Mr. Lea and others as to the propriety of separating 

 these genera. The most important facts developed, are that 

 the sexes are distinct in the Strepomatidije, and that our spe- 

 cies are oviparous, while the Oriental Melanians are ovo-vivi- 

 parous. Dr. Stimpson states that the differences in the animals 

 of Tryp)anostoma and Goniohasis, as described by Dr. James 

 Lewis, (Pro. Acad., Feb., 1863,) are only sexual differences. 



We are not surprised that the real differences in the 

 animals of our various genQmof Strepomatidse have not yet been 

 detected. The failure to do so, only shows that as a means of 

 distinguishing genera, Conchology is still far in advance of 

 Malacology. No one will presume to question the validity of 

 these genera, founded on the shell alone, or that correspond- 



