52 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. M. 



preceding turn into the umbilicus, completely plugging it, breathing 

 being effected through the axial puncture at the decollated apex. 



Interesting as these character are, they must be considered as of 

 secondary systematic importance to those of the operculum. The 

 latter develops its characteristics at an early stage of the mollusk's 

 history, while the breathing device, with the exception of RJiytido- 

 thyra Mlahiatum Orbigny, is developed near the final stage of the 

 shell growth. Then, too. we find quite similar devices in the family 

 Cyclophoridae, all of which strengthens the position of the opercular 

 features as prime factors in phylogenetic classification, which is 

 also more in harmony with the sum total of the characters pre- 

 sented by the shell. 



CHRONOLOGICAL REVIEW OF THE SUPERSPECIFIC NOMENCLATURE 

 OF THE ANNULARIIDEA. 



nnaeus, ]\Iulier, Lamarck. Wood, and other early authors who 

 described the first species of this family, employed the generic names 

 of Turbo, Nerlta, TmncatelU. and finally Cydostoma. This latter 

 name proposed by Draparnaud in 1801, in his Tableau dc Mollusquos, 

 had been unfortunately used by Lamarck for a marine mollusk. 

 '' Cydostoma'' was nevertheless indiscriminately used for a century 

 by many authors in describing a host of species, both from the New 

 and the Old World. This use continued even after the adoption of 

 a number of genera created especially for various groups of American 

 species. C. B. Adams, Pooy. Orbigny, Morelet, and Gould may be 

 cited among others who preferred ''Cydostoma" to the newer titles. 

 The name was later expanded to family rank as the "Cyclostomatidae" 

 or ''Cyclostomacea" and as such has included both European and 

 American forms save those that in 1885 were removed by Crosse to 

 constitute a separate family — the Cyclophoridae. 



The following is a chronological list of the genera heretofore founded 

 upon New World species : 



1797. Cistula (Humphreys) Museum Calonianum, p. 62. By 

 reason of the opinion of the International Commission on Nomen- 

 clature as set forth in Smithsonian Publication No. 2060, in February, 

 1912, this work is excluded from scientific nomenclature, hence the 

 name of Cistula as therein proposed can not be considered. 



1801. Cydostoma Drapernaud, Tab. Moll. France, p. 37, and later 

 exemplified in his Hist. Nat. Moll. France (1805), pp. 25, 74. The 

 name was preoccupied by Lamarck in 1779, liaving been applied by 

 him to a marine moUusk. 



1810. Cydostomus Montfort, Conch. Syst., p. 287. Type, Cydos- 

 tomus elegans Miiiler, of southern Europe. 



1817. Anmdaria Schumacher, Essai Nouv. Syst. Hab. Vers Test., 

 pp. 60, 169. This name was wTongfully invalidated by Herrmannsen 



