32 : Paleozoic Gastropod Genotypes

This work consists of descriptions and illustrations of the genotype species of each generic name proposed for Paleozoic Gastropoda prior to 1938. For the descriptive matter, which constitutes the body of the text, the arrangement is alphabetical. The arrangement of the illustrations on the plates, however, is arbitrary; an attempt has been made to place close together and on the same plate, insofar as possible, the illustrations of species that should be seen together for comparison. This results in a morphological grouping of species that incidentally approaches roughly a taxonomic one. In some points the arrangement is not entirely uninfluenced by taxonomic considerations, else there would be a tendency to group together homeomorphic species that show superficial similarities to the detriment of groupings of forms with what is regarded as more fundamental likenesses.

For the student who wishes merely to learn the genotype and its characters, the use of the work is very simple. He merely turns to the name desired in the alphabetically arranged text, and from that to the plate reference. On the other hand, the student who wishes to study genera in contrast to generic names, or who wishes to determine the proper generic name to apply to some species, will have at hand for the first time the basic material. He will have to start with the plates and acquire some familiarity with them. Using the plates in conjunction with the text, he will arrive at his own conclusions as to the . .