This volume contains a transcript of the original French text and an English translation of the six manuscripts of Lamarck in the library of the Museum of Comparative Zoology. The first manuscript, a lecture on Gall’s conception of the human brain, is of unusual interest because so little is known concerning Lamarck’s medical education. The sixth manuscript contains an account of an eighteenth century botanical excursion. A few of the drawings which accompany the text of one of the manuscripts are reproduced, and a general account of the various manuscripts, with Crookshank’s comparison of the life-plans of Lamarck and Darwin, is given in the Introduction.

During 1935 Dr. Neal Albert Weber, a pupil of Professor Wheeler’s, collected in Trinidad, B. W. L, the entire personnel of two large ant-colonies which contained unprecedented numbers of anomalous individuals. The present volume deals with the smaller colony, which is that of a fungus-growing (Attine) ant, Acromyrmex octospinosus Reich. This contains only 164 anomalous individuals, but fifty-three of these are of unusual interest both because they are quite unlike any previously observed among ants or indeed among any other social insects, and because they contain the solutions of the problems of caste determination in ants which have been bothering students of ants for the past half century.