Echinodermata, represented by a large number of both living and fossil forms, was made the subject of study the second winter. The common starfish was examined in detail, and with it were compared other members of its class—Asteroidea, living and fossil forms in Ophiuridea and Echinoidea, the modern Holothuroidea, the ancient Blastoids and Cystoids, and both extinct and modern Crinoids, the last of which were illustrated by alcohol specimens of Comatula. Professor Hyatt was assisted in giving these lessons by Miss J. M. Arms, who, in conjunction with him, had previously written the largest of the Science Guides—entitled Insecta—and by Dr. Robert T. Jackson, who has done much work on this group of fossils. One member of the class a few years ago, after receiving these lessons, looked over and prepared a large number of fossils, principally Crinoids, belonging to the Natural History Society, and discovered a form of paleozoic Echinoderm, which proved to be an interesting new species and was described by Dr. Jackson as Lepidesthes Wortheni.
The third year of this series consisted of lessons on Brachiopoda exclusively. Professor Hyatt was at that time in correspondence with Dr. C. E. Beecher, of Yale, the distinguished paleontologist, who has made remarkable discoveries and was then investigating Brachiopoda, and communications from him regarding this group were from time to time read to the class. "The sudden expansion or the quick evolution in the earlier periods of the earth's history and the slower evolution of the same types in their progressive history, after a period of sudden expansion had been passed through," were shown in several series.
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.