394 Quarterly Journal of Conchology. 



U. AVARDii, Lea. Rare here, common in the Cedar and Des- 

 Moines. It is a var. certainly of metincvius. It is a 

 beautiful shell, 



U. ZIGZAG, Lea. Common; Mississippi. I do not see clearly the 

 difference between this species and donaciformis, Lea. 



It may be we have both here; if so one is doubtless a 

 var. of the other. 



Corbiculadae. 



Sph.^rium stamineum, Conrad. Abundant in ponds and slow 



running water. 

 S. TRANSVERSUM, Say. Common with siamineum. 

 S. SPH^RiuiM, Anthony. Common in ponds in vroods. 

 PisiDiuM COMPRESSUM, Prime. Rare. In ponds in woods. 



Jan., 187S, 



NOTE ON THE GEOGRAPHICAL DISTRIBUTION OF 



TERRESTRIAL MOLLUSCA. 



By W. G. PETTERD. 



I have perused with considerable pleasure and instruction 

 the excellent article in the Q.J. C. for November, 1877, by C. P. 

 Gloyne, entitled, " Remarks on the Geographical Distribution of 

 Terrestrial Mollusca." Of course it could not be expected in 

 such a wide field as the title offers that the author could go 

 minutely into the details of the peculiarities of distribution in 

 each region. As far as he has gone it is remarkably good ; never- 

 theless I do not think a few additional general remarks concerning 

 the Australasian Province would be altogether uninteresting, or 

 that the author will think me intrusive. A task of this sort must 

 of necessity contain some little deficiences or even errors that it is 

 possible for those who have had local experience to expand or 



