THK NAUTILUS. 139 



mon than M. albolabris. M. dentifera was only seen in very dark, 

 cold, wet swamps, in places where T. palliata seemed to flourish 

 best. M. sayii was found on hills in dry places. I have noticed a 

 curious habit of economy in some specimens of 3/. thyroides. On 

 watching them crawl alternately over very rough and glazed paper, 

 I saw that while moving over the rough paper the whole length of 

 the foot was upon the paper ; but on glazed paper the animal would 

 only touch the paper in two or three points, keeping two or three 

 parts of the foot free from the paper. Thus, the track of the snail 

 over the glazed paper consisted of a series of spots of dried slime 

 where the foot had touched, while the intermediate spaces were per- 

 fectly clean. H. lineata was usually found in wet and rocky places. 

 P. striatella was found in similar locations, while P. perspediva was 

 found under logs and chips of wood in dry places far removed from 

 bodies of water. P. alternata hibernates in large communities ; forty- 

 four specimens, over a year old, Avere found under a single over- 

 turned rotten stump. T. carolinensis usually in rotten logs, but 

 sometimes climbing trees. T. dorsalis in very wet places. H. 

 indentata, radiatula and nitida were most abundant in damp places. 

 Z. inornatus usually in the valley, while Z. IcBvigatus and intertextns 

 were most common on hills and rocky places. Vitrina was only 

 found on a low island in a pond, almost at the water's edge. L. 

 maximus was sometimes seen quite a distance from buildings. *S'. 

 concava was most common in rockv situations. 



A FEW QUERIES AND NOTES. 



BY T. WAYLAND VAUGHAN. 



In the discussion of Messrs. Simpson and Dean, relative to the 

 distinguishing characteristics of Unio radiatus Barnes, and Unio 

 hdeohis Lamarck, one point seems not to be brought out, that would 

 surely interest all lovers of Najades. Are there ever any variations 

 that show the gradual vergence of the hard, highly polished 

 epidermis of luteolus into the rougher epidermis of radiatus ? 



Of hydianus, a close relative of luteolus, I can say : to-day, I 

 examined over 250 specimens (I counted the specimens), from four 

 streams in Northwest Louisiana, to see what variation there might 

 be in the character of the epidermis. In nearly every specimen, the 

 epidermis was perfectly smooth, glass-like, throughout. In a few 



