1896.] 285 



NEW BOOKS ON BRITISH ZOOI^OGY. 



The Collector's Manual of British Land and Freshwater 

 Shells. By IviONEi. K. Adams. 2nd Edition; pp. 214; pis. x. ; 

 8vo. Leeds : Taylor Bros., 1891. Price, 8^. (with coloured plates, 10s.) 



The aim of Mr. Adams' little book is to give a critical treatise on the 

 British Land and Freshwater Mollusca, with concise descriptions and 

 with an account of their habits. It contains also hints on the preserva- 

 tion and arrangement of shells, and, as stated on the title-page, it 

 purports to furnish us with the names and descriptions of all the varieties 

 and with synoptical tables showing the differences of species difl5cult of 

 identification. 



The only work with which this can at all be compared is that by 

 Lovell Reeve published in 1863, and now out of print, and though it 

 shows a very considerable advance on it in some respects, it falls short 

 of it in others. For instance, there is hardly any synonym}' given by 

 Mr. Adams, nor is there any mention of the distribution of the British 

 land and freshwater mollusca outside the British Islands. Then why 

 should Pahuiestrina jilvcr, Otina otis, and the genera Melampus and Alexia 

 be omitted, whilst Pahukstrina similis and P. ventrosa are described 

 in the work ? They are all more or less brackish forms, and all their 

 nearest relations are t3'pical freshwater species. 



It is to be regretted that Mr. Adams should have adopted the absurd 

 custom of attaching Latin names to mere normal variations, whilst the 

 system of bestowing varietal names should be carried out strictly in 

 accordance to the law of priority. The variety roseolabiata of Helix 

 netnoralis was described and named by Dr. Kobelt long before Mr. 

 Taylor attached his name to it. 



In many other cases foreign authorities have not been sufficiently 

 consulted. Dr. Bottger, the highest authority on Clausilia, has pointed 

 out that the so-called varieties Everetti (Miller) and tumidula ( Jeffr.) of 

 Clausilia bidentata are type forms of that species, whilst all British forms 

 of the latter may be grouped under the three varieties, gracilior, septern- 

 trionalis, and exigtia, only one of which is referred to by our author. 

 Helix costata and Hyalinia contracta are now almost universally looked 

 upon as distinct species, and not as varieties of H. pukhella and H. 

 crystallina. Of Helix sericea, which was identified as such from Yorkshire 

 specimens sent by us to Drs. Bottger and Westerlund, there is no 

 mention at all. The latter, moreover, thinks it very doubtful if the 

 Helix itala of Linne (p. 83) can really be referred to H. ericetortim, and 

 before making such a sweeping change in a well-known old name, the 



A3 



