36 



THE NAUTILUS. 



been largely neglected." Conchologists everywhere will heartily 

 agree with the opening paragraph of Mr. Woodward's book, quoted 

 above, which is true not only of British Pisidia, but of the genus 

 throughout its range. 



In the discrimination of species, characters of the hinge are chiefly 

 relied upon, the forms of the individual teeth and other details of 

 hinge-structure affording criteria of far more value, according to Mr. 

 Woodward, than external shape and sculpture of the shell. " In 

 one locality, all the species will exhibit less sculpturing than the 

 normal forms ; in another, more ; all may be dwarfed or all abnor- 

 mally large ; occasionally one species in the gathering will show 

 greater increase in size over the average, while its associates are 

 undersizfd ; or exaggerated inflation may be the prevailing feature." 

 While other authors have described the teeth of Pisidia, the subject 

 has never before been dealt with in the thorough manner of this 

 work. The terminology of M. Felix Bernard is used in the descrip- 

 tions of hinges. 



The author does not venture to establish subgenera, and seems 

 skeptical of those proposed by other writers. 



Seventeen species are recognized, fourteen of them living in the 

 British Islands, two extinct. The work on British forms necessi- 

 tated a critical study of practically all Palsearctic Pisidia, a couple 

 of hundred described forms, most of them synonyms or indetermi- 

 nate, so that the scope of the work is far broader than its title 

 indicates. Distribution, both recent and as fossils, is dealt with in 

 the most ample manner. The plates illustrate very fully the local 

 variations, the figures being photographs enlarged two to three 

 diameters and reproduced by gelatine process. It may be questioned 

 whether a smaller number of larger figures would not be more use- 

 ful. There are also four plates of much enlarged figures showing 

 the hinges. 



Whether the development of methods, the examination of vast 

 numbers of specimens from many localities, or the study of an in- 

 volved and exasperating literature is considered, the practical con- 

 chologist will realize that Mr. Woodward's task has involved an 

 enormous total of work. Notwithstanding its geographic limitations 

 we believe that the Catalogue will initiate a new epoch in the study 

 of this family, all over the world. H. A. P, 



