

SPECIES OF riSIDIVM. 87 



moderately swollen (PI. XXII, f. 10) but frequently tends to become 

 considerably so (PI. XXII, f. 17). This latter feature is frequent 

 in Irish specimens, "which often attain a large si/.e in localities 

 where the associated species of the genus are undersized. One of 

 the most elongate examples seen came from Salisbury (PI. XXII, f. 2) 

 and coming from running waters has the hinge strongly developed 

 in contrast to those from quieter waters as Lochmaben (PL XXII, 

 f. 8) and Bracebridge (PI. XXII, f. 7), which are both less elon- 

 gate and weak in the hinge, whilst examples from Rhosneigr 

 (Anglesey) (PI. XXII, f. 6) are comparatively round. Fossil 

 examples from the Strand, Newbury, and from Gayfield, Edinburgh, 

 have the umbones greatly developed, and so to a less extent has the 

 figured recent specimen from Gloucester (PI. XXII, f. 26)". 



DISTRIBUTION. 



SI 

 01 



NS CA 

 HB S3 



RW RE EL BF AN 



Wl El PN AS 



AM PM FF Kl 



M j)'*| 86 PC KF 



1 CT RF LL L2 HD 



AY LA PE BW NN 

 WO EO LO AN WT KB DF SK RX 8N 



f TY AR D _i CU WL NY N 



WM SI LE MO IM ML MY EY 



EM RO CV LH A SL WY SY LN 



WG NG LF W H Mf CR DB FT CH DY NM LS 



sT KG KD oT Mo SP ST LR CB WN ^ 



CL NT QC CW w , CD RA HF W0 ** N0 HU ** E_S 



NK LK ST KK wx PB CM BR fiE J1 ii BD HT g 



SK MC EC WA GM MM 6W NW ^n" 



"S SW M -W EK 



SS DT SH WX EX 

 EC SO IW 



SC WC 



Gl 

 Pisidium subtnuicatum. 



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

 below the symbols. For the explanation of the symbols see p. 20.) 



wc 



