NATURE 



THURSDAY, NOVEMBER 9, 1871 



THE ORIGIN OF GENERA * 



ALTHOUGH it is now two years since the publica- 

 tion of Prof. Cope's " fragmentary essay," as he 

 modestly terms it, bearing the above title, it may not be 

 out of place, in the present stage of the theory of Evolution, 

 to give our readers some idea of its scope. It ought to 

 be in the possession of every naturalist. Although 

 already so condensed that anything like an analysis of 

 it is impossible, the following tabular sketch may serve to 

 give our readers an idea of the mode in which the Origin 

 of Genera is treated : — 



I. Relations of allied genera. 

 First ; in adult age. 



Second ; in relation to their development. 

 a. On exact parallelism. 

 /3. On ine.xact or remote parallelism, 

 y. On parallelism in higher groups. 

 8. On the extent of parallelisms. 

 11. Of retardation and acceleration in generic character?. 

 First ; metamorphoses in adult age. 

 a. The developmental relations of generic and 



specific characters. 

 0. Probable cases of transition, 

 y. Ascertained cases of transition. 

 Second ; eailier metamorphoses. 

 S. The origin of inexact parallelisms. 

 III. Relations of higher groups, 

 a. Of homologous groups. 

 /iJ. Of heterology, 

 y. Of mimetic analogy. 



IV. Of natural selection. 



a. As affecting class and ordinal characters. 

 /3. As affecting family characters, 

 y. As affecting generic characters. 

 h. As affecting specific characters. 

 f. On metaphysical species. 



V. Of epochal relations. 



Professor Cope considers that the laws which ha\'e regu- 

 lated the successive creation of organic beings are of two 

 kinds. The first, that which has impelled matter to pro- 

 duce numberless ultimate types from common origins ; the 

 second, that which expresses the mode or manner in which 

 the first law has executed its course, from its commence- 

 ment to its determined end, in the many cases before us. 



" That a descent, with modifications, has progressed 

 from the beginning of the creation is exceedingly probable. 

 The best enumerations of facts and arguments in its favour 

 are those of Uarwin, as given in his various important 

 works, ' The Origin of Species,' &:c. There are, however, 

 some views respecting the laws of development on which 

 he does not dwell, and which it is proposed here to 

 point out. 



" In the first place, it is an undoubted fact that the 

 origin of genera is a more distinct subject from the origin 

 of species than has been supposed, 



"A descent with modification involves continuous series 

 of organic types through one or many geologic ages, and 



• " On ihe Origin of Genera." By Edward D. Cope, A.M., Corresponding 

 Secretary of the Academy of Natural Sciences of Philadelphia. Pp. 80. 

 1869. (Philadelphia: Merrihew and Son. London: Triibner and Co.) 



the co-existence of such parts of such various series at one 

 time as the law of mutual adaptation may permit, 



" These series, as now found, are of two kinds : the 

 uninterrupted line of specific, and the same uninterrupted 

 line of generic characters. These are independent of each 

 other, and have not, it appears to the writer, been developed 

 pari passu. As a general law, it is proposed to render 

 highly probable that the same specific form has existed 

 through a succession of genera, and perhaps in different 

 epochs of geologic time. 



" With regard to the first law of development as above 

 proposed, no one has found means of discoverin<r it and 

 perhaps no one ever will. It would answer such questions 

 as this. What necessary coincidence of forces has resulted 

 in the terminus of the series of fishes in the perches as its 

 most specialised extreme .' or, of the batrachia, in the 

 fresh-water frogs, as its ultimum .^ or, of the thrushes 

 among birds, as their highest extreme.' in a word, what 

 necessity resulted in man as the crown of the mammalian 

 series, instead of some other organic type 1 Our only 

 answer and law for the questions must be, the will of the 

 Creator. 



" The second law of modes and means has been repre- 

 sented to be that of natural selection by Darwin. This 

 is, in brief, that the will of the animal applied to its body 

 in the search for means of subsistence and protection 

 from injuries gradually produces those features which are 

 evidently adaptive in their nature. That, in addition, 

 a disposition to a general variation on the part of species 

 has been met by the greater or less adaptation of the 

 results of such variation to the varying necessities of their 

 respective situations. That the result of such conflict 

 has been the extinction of those types that are not adapted 

 to their immediate or changed conditions, and the preser- 

 vation of those that are " (pp. 4, 5). 



In the chapter " On the relations of nearly allied 

 genera," he gives no less than eight "examples of exact 

 parallelism."* We select one at random as illustrating the 

 large number of facts he brings to bear on the subject 

 of which he treats. '' The Cervids of the Old World are 

 known to develop a basal snag of the antler at the third 

 year ; a majority of those of the New World never 

 develop it, except in abnormal cases in the most vigorous 

 maturity of the most Northern Cariacus : while the South 

 American Subulo retains to adult age the simple horn of 

 the second year of Cervus. Among the higher Cervida 

 Rusa and Axis never assume characters beyond an 

 equivalent of the fourth year of Cervus. In Dama, on 

 the other hand, the characters are assumed more rapidly 

 than in Cervus ; its third year corresponding to the 

 fourth of the latter. Among Ainerican deer there is the 

 Blastocerus, whose antlers are identical with those of the 

 lourth year of Cariacus. 



" Now, individuals of the genus Cervus of the second 

 year do not belong to Subulo, because they have not as 

 yet their mature dentition. Rusa, however, is identical 

 with those Cervi whose dentition is complete before they 

 gain the antlers of the fifih year. When the first trace of 

 a snag appears on one beam of Cariacus virginianus, the 



* The author applies the term exact paraiklUiji to the relation of geneta 

 which are simply steps in one and tne .'auie hue of development ; wlii e iti- 

 co)iiptctc paraUeiism is applied to that of those w4lereone or more characters 

 intervene in the maturity of either the lower or higher gwiera to destroy 

 identity. 



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