THE NAUTILUS. 51 



light band. The anterior light band is about as wide as the dark. 

 The posterior one is scarcely indicated, being represented by a mere 

 line. The nepionic whorls of the two shells are also different : that 

 of oregonensis being papillose while that of the dupetithouarsi is 

 wrinkled. The young oregonensis is also much larger considering 

 the same number of whorls in the two species. Then too, the sculp- 

 ture of the adult whorls is quite different ; in oregonensis we have a 

 surface which is covered by a crinkly epidermis, the crinkles 

 placed obliquely. The lines of growth are irregular and not well 

 marked, while in the dupetithouarsi we have regularly impressed 

 lines and none of the crinkled epidermis, the latter being smooth ; 

 dupetithouarsi has a well-rounded spire while in oregonensis it is 

 flattened, etc. I believe that oregonensis comes nearer to the 

 group of E. mormonum than E. dupetithouarsi, You have the types 

 of cola and buttoni, so I will leave the comparison of them with you." 

 It seems from the above that we will have to write oregonensis 

 in place of mormonum, but whether Lea's name applies to the typical 

 middle Californian mormonum or to one of the described sub- 

 species remains in doubt. Adult specimens from Oregon are needed 

 to settle this question. 



H. A. P. 



LAMPSILIS VENTRICOSA (BARNES) IN THE UPPER POTOMAC DRAINAGE. 



BY A. E. ORTMANN. 



Some time ago the writer reported (Mem. Carnegie Mus., 2, 1906, 

 p. 373) that a western species of crawfish. Cambarus obscurus Hagen, 

 is found in the Potomac drainage, in Wills Creek, at Ellerslie, Alle- 

 gany Co., Md., and Hyndman, Bedford Co., Pa. This fact was dis- 

 cussed on p. 445 (1. c.), and explained in general terms as an "arti- 

 ficial introduction by human agency." I may add that this crawfish 

 apparently has increased in numbers since its first discovery (August 

 10, 1904, and May 8, 1905), for on September 7, 1909, I found it 

 very abundantly at Hyndman (for about a mile in the creek above 

 the tannery). And further, on May 6, 1912, this species was seen 

 in the South Branch Potomac at Romney, Hampshire Co., W. Va. 

 Although only a cast-off shell was found, this was of a male of the 

 first form, and positively established the presence of this species at 

 this locality. 



