The ancestral form of this group, the phylembryo, has been found in _Paterina_, whose adult represents the youngest stage, the beak of the shell, of other _Brachiopods_. There was, therefore, unusual opportunity to here illustrate theories of evolution, particularly the theory of constitutional tendency involving a conception of the youth, maturity, and senescence of species. In order to make the instruction clearer, terms used for the different stages of development by Professor Hyatt in his writings on bioplastology were explained to and used by the class. The many specimens used in this study were carefully figured in the notebooks, and the teachers became so familiar with them that they were able to pass at the end of the term a severe examination. The final test of the season's work consisted of three parts: The passing in of lecture notebooks, the naming and classifying of a dozen fossils selected by the professor, and the answering of a set of difficult questions. On account of the amount of time required for this course, and because the lessons were such as were not directly applicable to work in the public schools, the attendance decreased. The number who continued, however, were those who felt that a broad scientific education is necessary to the best teaching of even elementary science. The fourth year was devoted to _Mollusca_, _Cephalopoda_ in particular, and the class was fortunate in having for its teacher one whose investigations in this latter group have given him world-wide fame. The evolution of the group from its straight radical form, now named and called _Diphragnoceros_, was traced through the bent, curved, and coiled forms of the _Nautiloids_, _Ammonoids_, and _Belamites_. The phylogeny of the _Ammonoids_ presented a complete cycle, late forms entirely uncoiling and presenting the straight characters of their ancestors. The study of _Cephalopods_ amply illustrated the neo-Lamarckian theory of evolution, including the inheritance of acquired characters which is now believed by most paleontologists. The fifth and last year of this course included the study of _Arthropoda_ and _Vertebrata_. The insects presented many illustrations for the theory of natural selection, which the neo-Lamarckians consider an aid, but a subordinate factor, in the origin of species. About this time Poulton gave a series of twelve lectures on animal coloration at the Lowell Institute, drawing his illustrations mainly from insects. Many of the students of The Teachers' School of Science in zoölogy and paleontology attended these lectures.