2 BULLETIN 68, UNITED STATES NATIONAL MUSEUM. 



group that in most cases it has not been necessary to coin new 

 denominations. The synonymy, which is often much involved, is 

 treated of in the text which follows. 



The classification adopted is essentially that proposed by us in our 

 synopsis of the family published in February, 1904. Some revision 

 and some additions as was expected have been found necessary. 



Many of the specific names given in the past by different authors 

 have been repeatedly used for different species, rendering it neces- 

 sary in many cases to give new ones. In all cases the synonymy of 

 group names adopted has been based on researches which began 

 with the typical species of the original authors, which in the case of 

 some of the more anciently named forms has involved no little 

 labor. 



When any doubt existed in regard to the internal characters the 

 specimens have been ground down until the pillar has been made 

 visible over a great part of its extent, and in all cases the characters 

 recorded are the result of microscopical examination. Only a few 

 of the many named forms have been inaccessible, as the collection of 

 the U. S. National Museum is remarkably rich in species of this 

 group, while the jvmior author, during a recent visit to England, has 

 been able to examine the original types of Carpenter and Adams in 

 the British Museum, and later visited Amherst, Massachusetts, to 

 confirm earlier notes on the types contained in the C. B. Adams 

 collection, the property of Amherst College. The Zoological Museum 

 of Berlin, Germany, submitted its entire collection for study, and the 

 authorities of the Zoological Museum of Copenhagen, of the Academy 

 of Natural Sciences of Philadelphia, and of Amherst College, of the 

 University of California, of the U. S. Bureau of Fisheries, of the 

 Field Museum of Chicago, of the American Museum of Natural His- 

 tory, New York City, granted facilities for study, for photographing 

 type-specimens or at various times loaned material required for 

 study. The facilities of the National Museum have, of course, been 

 at the disposition of the writers, and most of the types of species form 

 part of its collection. 



The amount of assistance rendered by private correspondents and 

 collectors has been very large. Many of the friends of the Museum 

 have sent in all their Pyramidellid material, and have allowed it to 

 remain for study, in some cases several years. Others have gener- 

 ously resigned the opportunity of working up themselves the material 

 they had collected and have donated to the Museum type-specimens 

 of rare and even unique forms. For this generous assistance we are 

 deeply indebted. Among those to whom we desire to make the most 

 cordial acknowledgment are Mr. and Mrs. T. S. Oldroyd, Mr. Herbert 

 N. Lowe, and Mrs. Eshnaur, of Long Beach, California; Dr. Fred 

 Baker, Prof. F. W. Kelsey, Mrs. Kate Stephens, Mr. Henry Hemphill, 



