The earlier memoirs of this series published (in the _Philosophical Transactions_), writes Professor M’Intosh in the _Scottish Review_ for 1900, “formed important evidence in the discussions which took place between Owen and Huxley in regard to the posterior lobe of the brain, the posterior cornu, and the hippocampus minor.” Professor Owen, at the Cambridge Meeting of the British Association in 1862, maintained, from specimens of the human brain in spirit, and from a cast of the interior of the gorilla’s skull, that in man the posterior lobes of the brain overlapped the cerebellum, whereas in the gorilla they did not; that these characters are constant, and therefore he had decided to place man, with his overlapping posterior lobes, the existence of a posterior horn in the lateral ventricle, and the presence of a hippocampus minor in the posterior horn, under the special division Archencephala. Moreover, he grouped with these features the distinctive characters of the foot of man, and showed how it differed from that of all monkeys. Flower’s accurate investigations enabled Huxley to substantiate his antagonistic position to Owen’s doctrines, viz., that these structures, instead of being the attributes of man, are precisely the most marked cerebral characters common to man with the apes. Huxley also asserted that the differences between the foot of man and that of the higher apes were of the same order, and but slightly different in degree from those which separated one ape from another. The result of this controversy was the overthrow (except in the mind and works of its author) of Owen’s separation of man on the one hand as the representative of a primary group—the Archencephala; and of apes, monkeys, Carnivora, Ungulates, Sirenians, and Cetaceans on the other hand, as forming a second group—the Gyrencephala.[6] As will be seen from the above quotation, this result was very largely due to the work of Flower, although it was brought into prominent notice by the superior fighting powers of Huxley, who was also an older, and at the time at anyrate, a better-known man. It may be added that Flower himself subsequently abandoned the use of the term “Quadrumana,” as distinguishing apes and monkeys on the one hand from man, as “Bimana,” on the other, and brigaded all altogether under their Linnæan title “Primates.” The contributions of Flower to our knowledge of (and, it may be added, to the clearing up of misconceptions in regard to) the mammalian brain, was, however, by no means confined to the Primates (man, apes, monkeys, and lemurs). On the contrary, his researches were of equal—if not indeed of more—importance with regard to the structure of that organ in the lower groups of the class, namely the marsupials and the monotremes (duckbill platypus and spiny ant-eater). In the well-known Reade Lecture of 1859, Professor Owen expressed himself as follows with regard to the brain of the two groups last mentioned:—