THE NAUTILUS. 115 
A.—Lip expanded or flaring. 
Zaplagius Pils., type D. navicula (= Otostomus Martens not 
Beck & Gray; Navicula Spix not Blainv.). 
Semiclausaria Pfr., type D. semiclausus. 
Drymeus s. str., types D. xanthostoma and hygrohyleus Orb. 
Neopetreus Mts., type D. altoperuvianus. 
B—Lip simple, arcuate. 
Mesembrinus Alb., type D. virgulatus Fér. 
Eudioptus Alb., type D. pseudosuccineus. 
(.—Apical sculpture not distinctly grated. 
Leivstracus Alb., type D. vittatus (not Liostraca Burm.). 
The genus Drymeus is represented within our limits by D. serper- 
astrus in Texas, belonging to the restricted section Drymeus, and in 
Florida D. dormani and marielinus represent a section perhaps re- 
quiring a new name. D. muitilineatus belongs to Mesembrinus. 
A certain number of Brazilian and Venezuelan forms, of which 
D. vittatus, the type of Albers’ group Leiostracus,is an example, 
have superficial vermiculate wrinkles on the upper portion, exces- 
sively fine, often indistinct, spirals on the lower portion of the second 
apical whorl. This is quite different from the usual evenly grated 
sculpture. It is often very indistinct. 
THE SIZE OF MUSSELS. 
BY W.S. STRODE, M. D., LEWISTOWN, ILL. 
Some time since, in conversation with an aged naturalist, I in- 
formed him that I had found a valve of Unio alatus Say, in Spoon 
River, Ill., that was nine inches long. He expressed surprise and 
said that he never saw a mussel of any kind over six inches in 
length, and, old as he was, he would walk five miles and go into 
water up to his neck to get a specimen above that size. Feeling a 
little taken back by his assertion, I determined to go home and make 
some measurements of my largest species of Spoon River Uniones. 
I was certain that I had several varieties that were above six inches 
in length. The following is the result of my measurements : 
U. anodontoides Lea, length 7 in., circumference 9 in. 
U. ligamentinus Lam., length 7 in., cireumference 103 in. 
