620 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XXII. 



PSTROPHITUS RADIATUS Conrad. 



* Alasmodonta radiala CONRAD, Am. Jl. Sci., XXV, 1834, p. 341, pi. i, fig. 10.' 

 Small streams of southern Alabama. 



HOMOGEN^E. 



Male and female shells alike, oval to elongate; beak sculpture coarse; 

 embryos filling the entire outer gills in the form of thick, smooth pads; 

 the ovisacs not separated by sulci. 



Genus ANODONTA (Bruguiere em.) Lamarck, 1799. 

 (Type, Mytilus cygneus Linmwis.) 



Mya LINNAEUS, part, Syst. Nat., 1758, p. 1158. 



Hmncp,a POLI, Test. Utriusque Sic., I, 1791, p. 31; II, 1795, p. 253. 



Anodontitea BKUGUIEKE, Jl. Hist. Nat., 1, 1792, p. 131. 



Anodonta LAMARCK, Prodrome Class. Coq., 1799, p. 87. 



Anodon OKEN, Lehrb. Nat. Zool., 1, 1815, p. 238. 



Anodonies CUVIER, Regne An., II, 1817, p. 472. 



Shell elliptical, thin, inflated, often slightly winged posteriorly; beak 

 sculpture consisting of rather numerous more or less parallel ridges, 

 usually somewhat doubly looped, and becoming slightly nodulous on 

 the loops; surface, generally smooth, shining; hinge edentulous, 

 reduced to a mere line, regularly curved; muscle scars rather faint; 

 nacre dull. 



Animal with the marsupium occupying the whole outer gills, when 

 filled forming a smooth, very thick, liver colored pad; gills free from 

 the abdominal sac from one-half to their entire length; palpi generally 

 large; branchial opening papillose; anal opening without papilhe, 

 though sometimes very slightly crenulate; superanal opening gener- 

 ally small, widely separated from the anal. 



(Group of Anodonta cygnea.) 



Shell very evenly rounded in front, pointed behind, the point elevated 

 above the base, more or less winged on post dorsal part, the line from 

 the posterior part of the wing to the hinder point usually incurved; 

 beaks flattened, the sculpture consisting of numerous more or less con- 

 centric ridges, which are sometimes broken up into rather irregular 

 corrugations. 



Animal with the inner gills the larger, free from the abdominal sac 

 nearly or quite their whole length; palpi large. 



1 1 can make nothing out of this, the figure being poor and the description 

 meager. Conrad places it in Strophitiis in his Synopsis, 1853. 



