THE NAUTILUS. 17 



are favorable they will migrate auainst the current as well as with 

 it. Any one who has ever collected these mollusks at all extensively 

 will notice their furrows on sandy or muddy bottom, often extending 

 for forty or fifty feet, and made apparently without any regard to 

 the direction of the stream. I am led from my observations to 

 believe that most of the unios if placed in favorable conditions 

 would migrate over considerable stretches of water in a comparatively 

 short period. 



PALUDOMUS PALAWANICUS, n. sp. 



BY DR. AUG. BEOT, GENEVA, SWITZERLAND. 



T. imperforata, globoso-turbinata, solidula, fusco-olivacea non- 

 nunquam obscure flammulata. Sjnra breviter exserta, subintegra, 

 sed superficialiter erosa ; anfract. 42-5, rapide crescentes, valde con- 

 vexi, vix infra suturam submarginatam paulo planulati, sub lente 

 tenuissime spiraliter striati et striis incrementi subgranosa decussati, 

 striis infra suturam et ad basin postioribus, filiformibus. Anfractus 

 ultimus magnus, basi striis elevatis filiformibus nonnulli distautibus, 

 ornatus. Apertura ampla, late ovata, intus fusco-brunnea, margine 

 dextro subserrato, vix incrassato, intus albo limbato ; columella 

 incrassata, alba, callo parietali albo crasso. 



Operculum ? 



Alt. 19 mm., lat. 17 mm. ; apert. alt. 13 mm., lat. 10 mm. 



Habit. I. Palawan, Philippines (legit E. L. Moseley). 



Shell globose with a short exserted spire, moderately thick, 

 dusky-olivaceous, sometimes with irregular translucent interrupted 

 flames. Spire short, almost entire, but superficially eroded. Volu- 

 tions 45-5, very convex, slightly flattened under the suture, which is 

 finely marginated, covered with fine spiral unequal strise, and 

 decussated by the lines of growth ; last whorl globose, with some 

 distant filiform strife at the base and along the suture. Aperture 

 "wide, ovoid, inside dusky-brown, sometimes with one or two narrow 

 pale bands; columella thickened, white ; outer lip obscurely ser- 

 rated, slightly thickened inside, white at the margin. 



This interesting new shell, although the operculum is unknown, 

 belongs certainly to the genus Pahulonms and is, I believe, the first 

 species of the genus mentioned from the Philippines. It cannot be 



