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Mineralogy and Geology and tlie charge of the Natural History 
Museum, following in succession on the study of Botany and 
Zoology, the subjects of Thomson’s former chairs, now completed 
his training as a Professor of Natural History. He devoted much 
time and attention to Palaeontology, and thus, in comparing the 
old world forms with those at present existing, obtained much 
useful insight into the relations between them. Under his guidance 
the Museum of the College was greatly enlarged, especially in the 
departments of Zoology and Palaeontology, and his efforts in this 
respect received the hearty co-operation of the president and vice- 
president. Specimens for teaching and for the enrichment of the 
museum were sought for everywhere, and properly arranged and 
classified. Whatever new objects possessed unusual interest were 
made the subjects of papers read before scientific societies, or pub- 
lished in the journals of the day. It was at this time that a paper 
appeared on a genus of Trilobites; this had been read before the 
London Geological Society. Another, on a fossil Cirriped, was 
published in the Annals of Natural History. One can well 
imagine the growing consciousness of power in dealing with fossil 
forms which Thomson’s previous knowledge of the existing living 
forms gave him, and that, as the accumulation of specimens pro- 
ceeded, the series would be seen to be in certain parts more or less 
complete, whilst in others it would be found wanting, and thus the 
necessity of further investigation would be pointed out. It was 
natural that, when he came to the collection and investigation of 
the numerous varieties of extinct forms of echinoderms, the eye 
which was always open to the charms of beauty should have been 
arrested, and that it should have occurred to him that what was 
needed for a complete understanding of them was a correct know- 
ledge of everything which their living forms could teach. From 
this time he returned to his study of the development of the larval 
forms of these low organisms, especially with reference to Comatula 
and Pentacrinus, no doubt with the hope of arriving at some 
general conclusions as to the relations of their peculiar mode of 
development with that of the higher animals, and of showing their 
connection with extinct forms. 
Mr J. Y. Thomson had found his Pentacrinus Europams in the 
Bay of Cork in 1823, and was thus the first to discover a recent 
