Anculosae of the Alabama River Drainage 



29. 



mis only, I was without bands and i was streaked with color irregularly- 

 after the pattern of the shells known as flammata. 



The columella of coosacnsis is smooth, regularly developed, the larger 

 callous at the top not particularly strong. As in the case of other species- 

 of this group, the outer edge of the columella is flattened near the umbil- 

 icus, being at right angles to the body whorl. This character is not al- 

 ways present or when present well marked. In color, the columella is- 

 purple or reddish, white being uncommon. In one lot, 87 had the columella 

 purple, 16 with it slightly colored red or purple, i with this inner lip 

 white. The peristome is straight or slightly curved near the suture^ 



The embryo shell seems to consist of about two small, smooth whorls,, 

 tightly coiled, sometimes elevated, sometimes on the same plane. Five or 

 six whorls for the fully grown shell are indicated. 



The operculum is elliptical or ovate, moderately heavy, light to dark red. 

 Lines of growth are fine to coarse. In some opercula these lines are cross- 

 ed at right angles by waving striae. Rest scars are not prominent or easily 

 to be differentiated from growth lines. Apex usually rounded, sometimes 

 acute. Curves of the margins unequal. The polar point is slightly raised, 

 and normally is upon or near the left margin near the base. The whorls are 

 three. The spiral development can seldom be made out; it is closely confin- 

 ed to the area near the polar point. 



Mcasurcmcnis of shells: 

 Altitude Diameter 



Mohr 



Anculosa griffithian-a Lea 



Fig. 15 



Anculosa griMthiana Lea. Proc. Amer. Phil. Soc., II, p. 83, luly, 1841. 

 Anculosa ruhiginosa Lea (?), Proc. Aiiicr. Phil. Sac. II, p. 83, July, 1841. 



Following the example of Tryon, collectors and authors have usually 

 given precedence to the name ruhiginosa, a species described by Lea at 

 the same time and upon the same page as griffithiano. The former species 

 was, however, put down as a shell of "Warrior River", whereas the locality 

 of the species under discussion here was given as the Coosa River. Only one 

 character — "columella, thick, dark purple" — appears to point to the Coosa 

 mollusk, while the rest of Dr. Lea's description of ruhiginosa can apply to 

 a smooth and fairly common form of A. plicata Conrad which does inhabit 



