40 THE NAUTILUS. 



descriptions to those of the published species. I fail to discover the 

 identity of Valvata mergella, Westerlnnd with Valvata striata, Lewis. 

 The proportions of the shell, number of whorls, elevation of the 

 spire, etc., etc., are not the same in the two species. I must add that 

 Dr. Westerlnnd was certainly acquainted with either Valvata sincera 

 or striata, as in the description of his mergella, he alludes to the o 

 already described Noi-th American forms ! 



I have recently described under the name of Liogyrus Lehnerti, 

 a shell that was sent me some five years ago, by Mr. E. Lehnert, who 

 discovered it in the Potomac, together with Gould's shell. The 

 operculum which / have not seen, proved to be Amnicoloid, hence the 

 species should be called Amnicola Lehnerti. It is a sinistrorse, not 

 "distorted" shell, and owing to the number of specimens already 

 known, it may be termed a constant form, for not counting my two 

 typical examples, Mr. Lehnert sent some to Mrs. Geo. Andrews, who 

 wrote about these, saying in was " indeed an interesting shell," and 

 besides those he undoubtedly possesses in his own cabinet, Mr. H. A. 

 Pilsbry saw others that permitted him to ascertain its generic position. 

 Distorted specimens are frequent, as the latter says, in fluviatile 

 shells, but sinistrorse monstrosities are very scarce, and hitherto two 

 or three species at most {Limnea peregra, Melantho decisa), normally 

 destral, have been found sinistral, and amongst these no Amnicola, 

 although specimens of this genus are profusely distributed in suit- 

 able stations in Southern Europe, North Africa and North America. 

 I hunted much for fluviatile shells in Europe, but never gathered 

 anv sinistral Anniicohe and other fluviatile species, and frequently 

 occurred to my notice trochoid or distorted specimens of Planorbis, 

 some with part of the whorls entirely loose from the preceding ones ; 

 this I observed in Planorbis nautilius, Planorbis complanatus, and 

 some of the allied species, also in a wonderful little shell found in 

 1884 by my .self in the river named "Gave de Pau " in S. AV. 

 France, and perhaps a Paladilhia. (I never attempted to describe 

 this single specimen, no other species of Paladilhia, having evei' 

 been discovered not even in that location by myself, but in that part 

 of France, by other naturalists ; hence I should reasonably suppose 

 it is really new, as it is difl^erent from the other PaladiUmc not only 

 in this character, the last whorl being entirely detached, but still in 

 shape.) The genus Liogyrus, Gill or " Lyogyrus " appears to 

 possess this only conchological character (the last whorl loose from 

 the preceding), by which it may be distinguished from some of the 



