Notices of New Books. 7589 



proof of this cannot be given than a circumstance mentioned by 

 Agassiz, namely, that having forgotten to ticket the embryo of some 

 vertebrate animal, he cannot now tell whether it be that of a mammal, 

 bird or reptile. The vermiform larvae of moths, flies, beetles, &c., 

 resemble each other much more closely than do the mature insects. 

 We occasionally, though rarely, see something of this kind in plants ; 

 thus the embryonic leaves of Ulex or furze, and the first leaves of the 

 Phyllodineous Acacias, are pinnate, or divided like the ordinary leaves 

 of the Leguminosae. 



Mr. Darwin looks upon rudimentary or functionless members as 

 either retrospectively or progressively implying progress, — little pages 

 in the history of individual species, parallel with the phenomena of 

 the extinction and first development of individuals as members of 

 groups. Some rudimentary organs are those that have become 

 functionless by disuse, and others may be the elementary stages of 

 future developments not yet entered upon their allotted functions ; 

 otherwise it would be impossible to account for their existence as the 

 result of natural selection taking at advantage of projitable variations. 

 At page 488 (third edition) Mr. Darwin says : — " Rudimentary organs 

 may be compared with the letters of a word still retained in the 

 spelling but become useless in the pronunciation, but which serve as 

 a clew in seeking for its derivation. On the view of descent with modi- 

 fication, we may conclude that the existence of organs in a rudimen- 

 tary, imperfect and useless condition, or quite absorbed, far from 

 presenting a strange difficulty, as they assuredly do on the ordinary 

 doctrine of creation, might even have been anticipated, and can be 

 accounted for by the laws of inheritance." At page 452: — " The wing 

 of the penguin is of high service and acts as a fin, and may therefore 

 represent the nascent state of the wings of birds ; not that I believe 

 this to be the case ; it is more probably a reduced organ modified by 

 a new function. The wing of the Apteryx is useless, and is truly 

 rudimentary. The mammary gland of the Ornithorhynchus may per- 

 haps be considered, in comparison with the udder of a cow, as in a 

 nascent state." At page 453 : — "It is an important fact that rudi- 

 mentary organs, as teeth in the upper jaws of whales and ruminants, 

 can often be detected in the embryo, but afterwards wholly disappear. 

 It is also, I believe, of universal rule that a rudimentary part or orgaii 

 is of greater size, relatively to the adjoining part of the embryo, than 

 in the adult ; so that the organ in its early stage is less rudimentary, 

 or even cannot be said to be in any degree rudimentary." Bearing in 

 mind Mr. Darwin's theory, that the embryo is a sort of epitome of the 



