2 2 NELSON AND TAYLOR: ON YORKSHIRE MOLLUSCA. 



Var. undulata Colbeau. 

 Shell with some transverse dark bands. 

 17. Wensleydale — One specimen in the River Ure at Hackfall ! 



:0 



Family PALUDINID^. 

 Genus PALUDINA Lam. 



This genus is widely distributed throughout the Northern 

 Hemisphere, to which portion of the globe it was formerly 

 considered to be confined. Several species have how- 

 ever been recently described by Mr. Smith and others from 

 Australia, thus extending its range southward. The Australian 

 species are all characterized by spiral sculpture and absence 

 of colour bands below the periphery. 



We have, however, but two species in Britain, neither 

 of which appear to have been found north of Yorkshire except 

 in ballast. 



This genus does not possess the cartilaginous stylet in the 

 stomach that the Bythiniae have. 



The Paludin^ are stated to bury themselves in the soil for 

 weeks or months together. 



Paludina contecta (Millet). 



Rare and very local. 



This species formerly abounded near York, where it was 

 first found by Mr. Bean, of Scarborough. Dr. North, of York, 

 writes : " More than twenty years ago P. contecta was abundant 

 in a ditch or brook by the side of the River Ouse at Clemen- 

 thorpe, just outside the city towards Bishopthorpe. The place 

 is now a foul ditch and a nuisance to the district, and the shells 

 and other interesting objects are gone." 



Trans.Y.N.U., 188a (pub. 1883). Series C 



