WEAVEk: INVERTEBRATE PALEONTOLOGY AND HISTORICAL GEOLOGY 709 



M. Neumayr investigated the hinge structure of bivalve shells and proposed a 

 classification based on the morphological characters of the teeth on the hinge 

 plate. H. Douville in 1912 grouped the Pelecypods on the basis of adaptive radia- 

 tion into a system, proposing three branches depending on the mode of life to 

 which the animal was accustomed. Investigations of both living and fossil mol- 

 lusks by W. H. Dall brought about a classification of the Pelecypoda in which 

 all characters of the shell were considered but with special emphasis on the de- 

 tails of the hinge plate. This grouping of families and genera was used in the 

 English translation of von Zittel's Handhuch der Palaeo7itologie in 1895 and in 

 1913 (Eastman, 1913), a grouping which, with many modifications, is in general 

 use at the present time. Other notable contributions to the morphology of spe- 

 cial groups of Pelec^'pods and Gastropods are those of R. T. Jackson (1890) on 

 the phylogeny of Pelecypods, F. Bernard (1895-1897) on the morphology of 

 the pelecypod shell, Charles Deperet and F. Roman (1902) on Neogene Pectens, 

 A, W. Grabau (1904) on the phylogeny of Fusus and its allies. 



Several students of Mollusca have published reference books and monographs 

 which are widely used by paleontologists engaged in the systematic description 

 of fossil pelecypods and gastropods. Among these are H. and A. Adams in 1858, 

 R. A. Phillipi in 1853, Tryon and Pilsbry's Manual of Conchology (1879-1898), 

 J. C. Chenu in 1859, and F. A. Quenstedt in 1881. The many publications by 

 M. Cossmann (1895-1925), including his thirteen-volume work Essais de paleo- 

 conchologie comparee, have been of fundamental importance for classification of 

 gastropod genera. The "Gastropoda" section of the Handhuch der PalaozooJogie 

 (incomplete) by AV. Wenz, 1938-1944, is an up-to-date and extremely valuable 

 treatment of this class of Mollusca. The Handhuch der systematischen Weich- 

 tierkunde, by Thiele, is important for a comparison of the use of soft and hard 

 parts of classification. One of the more recent contributions is Tertiary Faunas, 

 by A. M. Davies (1934-1935). This work considers genera of Foraminifera, 

 Echinoidea, Pelecypoda, Gastropoda, and some vertebrates characteristic of the 

 Tertiary throughout the world and presents the morphological characters that 

 distinguish genera, along with their stratigraphic range and geographical distri- 

 bution. The early half of the twentieth century saw the publication of a very 

 extensive literature by W. H. Dall and P. Bartsch on both fossil and living mol- 

 lusca. These works deal with faunas of particular areas or with biologic groups. 



A very extensive literature in which fossil mollusks are described deals with 

 faunas of particular formations, with emphasis on stratigraphic problems. The 

 importance of geology to the world-wide growth of the oil industry has stimu- 

 lated research in stratigraphy and in the use of fossils to establish the time 

 sequence of faunas. The result has been the publication of many papers with 

 lists of faunas and the occasional description of new species. 



Some of the more significant contributions of a purely scientific character 

 during the past one hundred years are those of James Hall on the Paleozoic 

 Mollusca of New York State, S. V. Wood on the Crag Mollusca of Great Britain 

 (1851-1861), Morris and Lycett on the Great Oolite (1850-1863), J. Barrande 

 on Silurian mollusks (1852-1899), Pictet and Campiche (1855-1872) on the 

 Cretaceous Molluscs of Switzerland, and F. A. Quenstedt on the Jura in 1858. 

 Papers dealing with the Mesozoic are those of A. Bittner (1895) on a revision 

 of the Pelecypods of St. Cassian; W. H. Hudleston (1887-1896) on British 



