THE NAUTILUS. 41 



turn up elsewhere in the Potomac. The localities known at 

 present are all to the west of the Blue Ridge Mountain, that is 

 to say, within the Great Alleghany Valley and the Alleghany 

 Mountains." 



Perhaps the above prediction has been realized in a specimen 

 found at Great Falls, Md., by Mr. Manly D. Barber of Knox- 

 ville, Tennessee, in Sept. 1915. At that time Mr. Barber 

 brought to the National Museum a basketful of naiades which 

 he had collected the same day at Great Falls, about 18 miles 

 above Washington. Among the shells, which were mostly dead 

 ones, was a specimen of cohongoronta, dead, but in a fine state 

 of preservation and with the periostracum nearly unblemished 

 except for the usual erosion at the beaks. Its appearance in- 

 dicated that it had been recently alive and that its home had 

 been in the immediate vicinity of the place in which it was 

 found. Had it been washed down from Harper's Ferry, some 

 50 or more miles above Great Falls it probably would have 

 shown ill effects from so long a journey. 



When found the two valves were separated, but so accurately 

 do they fit together that it is evident they belong to the same 

 individual. The fact that the valves were separated and yet 

 were found near each other is additional (though not conclu- 

 sive) evidence that they had not been transported any great 

 distance by currents. At any rate this is the first recorded 

 finding of the species in the Potomac River so far south as Great 

 Falls. 



The specimen is rather a small one. It measures, length 71 

 mm. ; height 47 mm. ; diameter 28 mm. It is in the collection 

 of the U. S. National Museum, catalogue number 273834. 



COLLECTING DAYS ABOUT THE NAVAL STATION, 

 GUANTANAMO BAY, CUBA. 



BY JOHN B. HENDERSON. 



In March last, while waiting for a boat to take us to Haiti, 

 Dr. Bartsch and I spent nearly three weeks at the U. S. Naval 

 Station at the entrance to Guantanamo Bay. We employed our 



