In the preparation of the introductory portion of the present 

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

 forming part of"' Broun's Klassen und Ordnungen d. Thierreichs:'' 

 — the most comprehensive treatise on the anatomy of the mollusca 

 which has yet appeared. Of course many a(hlitional 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. 1 hMve endeavored to avoid the prolixity of 

 Keferstein without sacriticing cleai'iiess of language, but occa- 

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

 alone am responsible, are made in the first [)erson. The l>ody of 

 literature consulted is too extensive for (juotation in a work like 

 this, where much must necessarily be saci'ificed for the sake of 

 brevity. Wliilst 1 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 ])resent a carefully arranged, concise account 

 of all that is known concerning the Murices and Purpurae. 



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. 



Jamtary. 1880. U. W. T.. Jr. 



