134 THE AMERICAN NATURALIST. [VoL. XXXII. 
PALEONTOLOGY. 
Harris’s Catalogue of Australasian Tertiary Mollusca.'— The 
catalogues published by the trustees of the British Museum gener- 
ally contain much more than their titles imply. In them will often 
be found some of the latest applications of the laws of evolution 
and the elucidation of new and important principles of morphology. 
Discussions of this nature have added value and weight from the 
intimate association of specimens and ideas, for usually curators 
of collections and custodians of ideas are too frequently dissociated. 
It is, therefore, a wise policy to engage the services of the highest 
talent in the preparation of the catalogues or reports on various 
collections or classes of organisms. 
Thirteen volumes on fossil vertebrates, eight on fossil inverte- 
brates, and three on fossil plants have already been published in 
this series, and Dr. Woodward states that thirty volumes more will 
be needed to include the remainder of the plants and Mollusca, the 
whole of the Brachiopoda, Annelida, Arthropoda, Echinodermata, 
and Ccelenterata. 
The present catalogue of the Tertiary Mollusca of Australasia is 
based upon the study of large collections, especially rich in well-pre- 
served Gastropoda. Mr. Harris has thus been enabled to study the 
larval shells and the stages of growth with accuracy and precision. 
In studies of phylogenies and in the systematic classification of 
the Gastropoda the results are important. The scaphopods and 
lamellibranchs are also included, but owing to meager material 
they have afforded insufficient data for general conclusions 
Some valuable suggestions are given governing the correlations of 
phylogeny with chronology. : Thus, a genus that has survived from 
early Mesozoic times, with but little modification in the later stages 
of its history, has had its day and settled down to a more or less 
fixed form. Such a genus is of little use for homotaxial purposes, 
though interesting phylogenetically. In the Tertiary the determi- 
nation of homotaxis can best be based upon families which origi- 
nated in Jurassic or Cretaceous times and reached the Eocene with 
strong tendencies to variation ; yet, at the same time, the members 
should be capable of wide and rapid dispersion. 
1 Catalogue of the pies Mollusca in the Department of Geology, British 
Museum (Nat. Hist.). Pt. i. The Australasian Tertiary Mollusca. By George 
Harris, F.G.S. 8vo, pp. i-xxvi, 1-407. Pl. I-VIII. London. Printed for 
the trustees. 1897. 
