THE NAUTILUS. 



113 



Young Arkansia are found in the shallow waters both on the 

 sand bars and muddy bottoms, but like other anodontine species 

 they prefer the oozy mud of the river margins where there is 

 little or no current. So far, the most patient effort to secure 

 gravid females of this new genus has not been successful, the 

 breeding season being winter, and the localities just described 

 being almost inaccessible at this season. 



Mr. Sampson in his " Preliminary Report of the Mollusca of 

 Arkansas," 1 enumerates twelve species of mollusks collected in 

 Clark County. Five of these I have not been able to verify, 

 namely: Physa gyrina (Say), which is possibly the same as 

 Physa anatina of my list, Campeloma subsolidum (Anth. ) which 

 is certainly what is now described by Walker as Campeloma 

 lewisii, Pleurocera subulare (Lea) which may be Pleurocera ele- 

 vatum (Say), Pleurocera canaliculatum (Say), and Goniobasis 

 lawrencei Lea. Mr. Call in his 4 'Study of the Unionidae of 

 Arkansas," 2 reports three species from the Ouachita collected 

 in Clark County, namely : Unio parvus Barnes, Unio subrostratus 

 Say, and Unio tumescens Lea. What Professor Call took to be 

 tumescens is very likely a juvenile Fusconaia undata (Barnes). 

 Many shells collected in late summer have a clear " honey 

 yellow color," and they are "abundantly rayed over the entire 

 surface," just as he describes the so-called tumescens. Lea was 

 surely mistaken in the locality given for his type specimen, for 

 the species belongs to the Tennessee drainage, and has not been 

 found, so far as I am aware, west of the Mississippi River. 

 The Arkansas range of this species is also questioned by Dr. 

 Walker in Simpson's u Catalogue of the Naiades." 3 



Annotated List of Species. 



Carychium exile H. C. Lea. Collected in one place only, a 

 marshy pasture along Mill Creek, an insignificant stream just 

 North of Arkadelphia. 



Lymn&a columella Say. Ouachita River under the Railroad 



'In Annual Report of the Geological Survey of Arkansas for 1891, Vol. II, 

 pp. 179-199. 



2 Transactions Acad. Scien., St. Louis, 1895, pp. 1-65, Plates I-XXL 



3 See in loco, p. 751. 



