1 5 Calvin Goodrich 



amount of material and was persuaded that Lea's formosa was synonymous 

 with A. ampla Anth., a decision possibly justified under the circumstances. 

 Mr. Smith was enabled to prove the specific identity of formosa from the 

 shells in the Schowalter collection which did not come to the eyes of either 

 Lea or Tryon. He himself collected a large series of these distinctive An- 

 culosae. An adult from Fort William Shoals, Coosa River, is here de- 

 scribed : 



Shell: Conic, thick, Dresden brown, shining. It has ten or twelve low, broad,, 

 rather obscure folds from shoulder to base. At the shoulder are irregular nodules 

 which in other shells often take the clear form of plicae. Microscopic lines of 

 growth are fine; no revolving striae save the channels between the folds were 

 observed. Suture impressed, irregular. Aperture ovate. A broad band appears at 

 the top of the aperture and another at the base. Between these two bands are six 

 or seven faint, interrupted fine lines of color such as occur in A. picta Con. Peristome 

 sharp-edged, but firm; slightly curving near the suture. Columella porcelain white,, 

 very strong, curving regularly, rounded, flattened slightly on the outer edge, a heavy 

 deposit of callous at the top, base unusually heavy. The shell is 19 mm. in altitude; 

 diameter, 1434 mm. ; aperture, 8;4 mm- by 7. Collected by Herbert H. Smith, July, 1913. 



The species first appears in the Coosa at Minnesota Bend, just below 

 Gadsden. It has there many of the aspects of A. dozuniei Lea which occurs 

 in the same shoals, being yellow or light brown, strongly folded and with 

 distinct plicae. There is a gradual modification of these characters pro- 

 ceeding down the river. At Ten Island Shoals the shells tend to lose the 

 plicae, to acquire a strongly shouldered appearance and to be slightly 

 ligulate. The middle and lower river form begins to show at Three Island 

 Shoals in Talladega County, though occasional mollusks above this locality 

 have the middle river aspect. At Fort William Shoals plicated specimens 

 are rather rare, smooth shells are more common than in the shoals above. 

 The lots from Weduska Shoals, The Bar, Butting Ram Shoals and Wet- 

 umpka are smooth, without folds or clearly marked plicae. 



Variations as to locality in the matter of banding are also noticeable. 

 Minnesota Bend shells have fine lines within the aperture, often nearly ob- 

 solete, which follow the folds of the outer surface. At Ten Island Shoals 

 a single shell was found which has three well marked bands of the usual 

 form, one above the periphery, two below it. More and more shells of this 

 character appear as the collections progress down the river. In one of the 

 lots from Fort William Shoals, 44 have the fine, broken lines typical of 

 picta with the addition of a heavy band at the base; 19 have the lines con- 

 tinuous together with the basal band ; 20 have an arrangement of four equi- 

 distant, clearly defined bands. Five modifications of this latter arrange- 

 ment were noted in a total of 28 specimens. In one lot from The Bar, near- 

 ly as many specimens had a few definite bands as had the many fine lines of 

 color. The two forms were of equal number in material from Butting Ram 

 Shoals. 



The prevailing color of the columella of the up-river formosa is white. 

 In a Fort William Shoals lot 85 shells had a white columella, 26 had the 



