Günther's classification would have been vastly improved had he made use of a contribution published as early as 1871, but not referred to by him. As not even a passing allusion is made to it in the previous chapter, we must retrace our steps to make good this striking omission. Edward Drinker Cope (1840-1897) was a worker of great originality and relentless energy, who, in the sixties of the last century, inspired by the doctrine of evolution, was one of the first to apply its principles to the classification of vertebrates. Equally versed in recent and fossil zoology, and endowed with a marvellous gift, or "instinct" for perceiving the relationship of animals, he has done a great deal for the advance of our knowledge of mammals, reptiles and fishes. Although often careless in the working out of details and occasionally a little too bold in his deductions, Cope occupies a high rank among the zoologists of the 19th century, and much of his work has stood the test of time. The following was Cope's classification, 1871 (_Tr. Amer. Philos. Soc._ xiv. 449). Subclass I. Holocephali. " II. Selachii. " III. Dipnoi. " IV. Crossopterygia, with two orders: Haplistia and Cladistia. " V. Actinopteri. The latter is subdivided in the following manner:-- Tribe I. : Chondrostei. Two orders : Selachostomi and Glaniostomi. Tribe II. : Physostomi. Twelve orders: Ginglymodi, Halecomorphi, Nematognathi, Scyphophori, Plectospondyli, Isospondyli, Haplomi, Glanencheli, Ichthyocephali, Holostomi, Enchelycephali, Colocephali. Tribe III. : Physoclysti. Ten orders : Opisthomi, Percesoces, Synentognathi, Hemibranchii, Lophobranchii, Pediculati, Heterosomata, Plectognathi, Percomorphi, Pharyngognathi. Alongside with so much that is good in this classification, there are many suggestions which cannot be regarded as improvements on the views of previous workers. Attaching too great an importance to the mode of suspension of the mandible, Cope separated the Holocephali from the Selachii and the Dipnoi from the Crossopterygii, thus obscuring the general agreement which binds these groups to each other, whilst there is an evident want of proportion in the five subclasses. The exclusion from the class Pisces of the Leptocardii, or lancelets, as first advocated by E. Haeckel, was a step in the right direction, whilst that of the Cyclostomes does not seem called for to such an authority as R. H. Traquair, with whom the writer of this review entirely concurs.