118 CATALOGUE OF 



Dimension*. Westerlund'a measurements are: Long. ^~i, 

 Alt. 3'5, Grass. Ji-5 mm., but a larger specimen in the National 

 Museum, Ireland, is Long. 4'5, Alt. 4 mm. The West Galway 

 specimens were smaller and less globose : 2-8 x 2*5 x 1'8 mm. 



The outstanding feature of the species, apart from its globular 

 form, is I he peculiar curve and twist, of the anterior principal 

 lateral teelh, with the deep fossae behind them. Xo similar 

 diameters occur in any of the members of the genus treated of in 

 this Catalogue. 



Judging from the specimens received from other plnces, there 

 can be no doubt but. that those from the type locality represent an 

 abnormally swollen form. 



D I S T R I B U T I O N. 



si 

 01 



ND S3 DT SH WX EX 

 EC SD IW 



SC WC 



Cl 

 Pisidium hibemicum. 



(Recent occurrences are shown in red : fossil occurrences by a line 

 below the symbols. lor the explanation of the symbols see p. "20.) 



