IN THE preparation of the introductory portion of the present 

 volume free use has been made of Keferstein's admirable work, 

 forming part of' 4 Bronn's Klassen und Ordnnngen d. Thierreichs:" 

 the most comprehensive treatise on the anatomy of the mollusca 

 which has yet appeared. Of course many additional facts and 

 some corrections have been published since the issue of that 

 work, and abstracts of the most important of these have been 

 herein incorporated. T have endeavored to avoid the prolixity of 

 Keferstein without sacrificing clearness of language, but occa- 

 sionally quote his very words. The few statements for which I 

 alone am responsible, are made in the first person. The body of 

 literature consulted is too extensive for quotation in a work like 

 this, where much must necessarily be sacrificed for the sake of 

 brevit}-. Whilst I have freely used the admirable illustrations of 

 Keiner, Reeve, Sowerby, Kiister, and other monographs, I have 

 added to these hundreds of figures, names and items of infor- 

 mation gleaned from fugitive papers and scientific periodicals ; so 

 that I am enabled to present a carefully arranged, concise account 

 of all that is known concerning the Murices and Purpurse. 



I may be thought by some, to have treated the species in a too 

 conservative spirit ; my object in the investigations of which 

 this work is the result, has been solely to ascertain truth, not to 

 establish, maintain or destroy scientific reputations. 



January. 1880. G. W. T., JR. 



