- 119 - 



Sinensions .- length, 8.5 mm.; alt., 6 mm.; semidiam., 2.2 

 mm.; length of hiiir-e, 5 mm. 



I^emark.? .- V.Tien oomnared with other specirens of this wide- 

 ly ranging species, it is a'oparent that the Bowden representatives 

 are sr.s.ller; the posterior ridge low^r; the ventral margin less 

 contracted and the edentulous gap in the hinge shorter. The deli- 

 cate cancellated sculpture formed by the "trailing blisters", as 

 Ball has hapoilj- described them, is very characteristic. The 

 blisters, however, are easily T^-orn off and all of the speci:-ens have 

 only a few of them remaining, the surfaces from which the blisters 

 heve been removed being almost smooth. The elevated rid,cres that 

 bound the muscle scars appear to better advantage on the posterior 

 scar. 



Recent specirens of this species apparently were early dis- 

 tribute^-- under the manuscript name of A. adamsi 3hattlev7orth and 

 Dall was the first, as Hiss Gardner has sho^^Ti, (1) to define It. ' 



(1). Mss. 



Smith, to whom the spe'3ics is usual:" y assigned, nin not publish 

 his description until two years later. 



Occurrence .- Clirocene.- Tampa silex bo'S, "lorida (Dall, 

 1898, 1915). Ohipola rnarl, ""lorida (Dall, lOOS). Oak Grove 



