JOURNAL OF CONCHOLOGY. 433 



iresult was as follows: — 'Coiled dextrally ; depressed, paucispiral, trans- 

 versely striate, sulcata, umbilicated, subcarinate periphery, rounded aperture, 

 peristome continuous.' The colour and size were purposely omitted. I should 

 hardly have applied the term paucispiral to the shell, but to do so was natural 

 enough in the light of the figures on p. 26. Westerlund goes into this matter 

 a little more fully, distinguishing between the gradually and rapidly enlarging 

 whorls separately from the question as to their number. Westerlund also 

 explains the meaning of ' penultimate whorl,' which perplexed my student. 



A few other points in the work deserve mention. The printing is most 

 excellent, and free from errors ; but the binding of my copy is rather unsatis- 

 factory. The plate is very good, the three varieties of H. aspersa being 

 especially excellent ; but I do not know why it was necessary to go to 

 Ferussac for a Lhnax inaximus. 



Credit is given to collectors of all specimens figured ; but it seems rather 

 unnecessary, in addition to this, to inform us to what learned society the said 

 collectors happen to belong ! 



I feel tempted to offer some criticisms of the remarks on varieties, bnt 

 refrain, as these are not concluded in the present part, and on previous 

 occasions I have said my say on this subject pretty fully. There is, however, 

 one point that should be emphasised. On p. 61 reference is made to the 

 palpable band-variations in Helix, which may be less important than more 

 subtle variations in form or character. It has been too little noticed, that 

 while a species may present similar variations in two localities, the average 

 appearance or facjes, of long series from these localities may be different. 

 These differences are often subtle, and only noticed when comparing 

 numerous specimens all together, yet they are certainly worthy of serious 

 attention. 



So far Part I. It may be said in conclusion that everyone who is 

 interested in British Moliusca ought certainly to have the book, and judge 

 for himself of its contents. To such persons it will be a necessity. 



T. D. A. COCIvERELL. 



Habitat of Unio pictorum v. platyrhinchoidea 



Dupuy. — On page 64 of Taylor's ' Motiograph of British Land 

 and Freshwater Moliusca,' there is a reference to the occurrence 

 of this variety in Hethersett Lake, with tlie remark that possibly 

 there was some peculiar feature in the lake which would assist 

 in accounting for the existence of this running-water form in that 

 locality. Hethersett Lake is about 200 yards long and about 

 50 yards wide. A small stream flows in at one end, a stream 

 quite three times as large flows out at the other end ; this differ- 

 ence in volume is accounted for by the fact that there are 

 numerous springs in the lake itself, which can be felt when 

 bathing, and which show themselves distinctly when the lake is 

 frozen. Perhaps this peculiarity accounts for tlie occurrence of 

 this variety. — A. G. Stubbs, November nth, 1S94. 



