130 THE NAUTILUS. 



GENERAL NOTES. 



VALLONIA PULCHELLA You may remember that in '97 I sent 



you a note concerning the sudden appearance of Vallonia palchella 

 in immense numbers in Pittsburg, Pa. A similar case has just been 

 brought to my attention by a friend who lives about 6 miles out of 

 town. Sometime in September he found his front walk (stone) cov- 

 ered with " thousands of small shells," and about two weeks later 

 they appeared again. He saved a few for me and they prove to be 

 Vallonia pulchella. Are such occurrences common? G. H. CLAPP. 



AN ADDITION TO THE U. S. LAND SNAIL FAUNA. For the past 

 three years I have had three adult and three young examples of a 

 Truncatella from Key West, Fla., collected by Hemphill, which I 

 had labeled, provisionally, T. bilabiata (they were sent as " T. pul- 

 chella var."), but which I was satisfied, from the very coarse and 

 widely-spaced ribs, were something else. Your Bermuda paper has 

 put me on the right track, as they agree perfectly with the "key" 

 to and figure of Truncatella clathrus Lowe, so we must add this 

 species to the U. S. fauna. G. H. CLAPP. 



PUBLICATIONS EECEIVED. 



SYNOPSIS OP THE NAIADES, OK PEARLY FRESH- WATEK MUS- 

 SELS. By Charles Torrey Simpson, viii + 544 pp. (Proc. U. S. 

 Nat. Mus. xxii, 1900.) This work presents an epitome of the 

 author's studies during many years upon the classification of the 

 fresh-water mussels, the synonymy of the species, and their geographic 

 distribution. It is, in fact, a continuation of the famous series of 

 synopses issued by ISAAC LEA ; an arrangement of the mussels, not 

 a work for the determination of species. 



The classification of the family Umonidse is almost completely 

 original with Mr. Simpson, and it need not be said, must appear 

 strange to those acquainted with the old arrangement of the group. 

 The treatment of Mutelidtz is less revolutionary. The fundamental 

 division of the Unionidce rests upon the nodifications of the ovisacs, 

 or modified gill pouches of the female carrying the embryos; the 

 sculpture of the beaks of the shell also affording characters of great 

 value, being shown to be correlated with features of the soft anatomy. 



