May 22, 1896.] 



SCmNGE. 



Ill 



the industry and ingenuity with which the pro- 

 cess of matching has been carried on." Prof. 

 George S. Huntington also recognizes the diffi- 

 culty in his admirable paper on certain muscu- 

 lar variations in the Transactions of the New 

 York Academy of Sciences. ' ' I believe that we 

 are right, ' ' he says, ' ' in referring such varia- 

 tions * * * to the development of an inherent 

 constructive type, abnormal for the species in 

 question, but revealing its morphological signifi- 

 cance and value by appearing as the normal 

 condition of other vertebrates." But if so are 

 we justified in calling them ' reversions ? ' 

 Dr. Huntington's views do not seem to differ 

 widely from those that I expressed in a paper 

 on this subject in the Naturalist, of February, 

 1895. ' ' Those very irregularities, which we 

 call abnormal, point to a law in accordance with 

 which very diverse animals have a tendency to 

 develop according to a common plan." I do 

 not need to be told that even to establish a law 

 (and I have only hinted at one) is not in the 

 least to show how it acts. All that I claim is 

 that some other principle than atavism must be 

 invoked. The pitiable abuse of it is shown in 

 a book that I met the other day on the vermi- 

 form appendix. After stating that this is to be 

 considered as the end of the caecum, the author 

 went on to remark that the rare cases of a 

 double appendix, which are said to have oc- 

 curred, are presumably to be explained by the 

 double Cccca found in many hirds. Dr. Frank 

 Baker, in the April number of the Anthropol- 

 ogist, severely criticises similar abuses. 



The question is associated with another of 

 very general importance, namely, whether simi- 

 larity of structure is necessarily evidence of de- 

 scent or even of relationship. One would think 

 from certain writings that it is conclusive; but, 

 of course, every anatomist knows that it is not. 

 It seems that similar special organs, or arrange- 

 ments of structures, occur in widely different 

 orders in species of similar habits or surround- 

 ings. Mr. Dobson* instances a South American 

 rodent with the habits of moles in which the 

 arrangement of the muscles of the leg is the 

 same as that of the true moles. This clearly 

 points to a law which, it seems to me, the oc- 

 currence of anomalies tends to confirm. It is 



* Jour. Anat. and Phys., Vol. XIX. 



in the hope of having this discussed that I lay 

 it before the readers of Science. 



Thomas Dwight. 



'peogress in american ornithology. 1886-95. ' 

 , In the American Naturalist for May (Vol. 

 XXX., pp. 357-372) Dr. R. W. Shufeldt gives, 

 under the above title, a statistical summary of 

 the new American Ornithologists' Union 

 'Check-List of North American Birds,' with 

 criticisms passim on various points, followed by 

 an arraignment of the Committee which pre- 

 pared it for ignoring all recent work on the 

 classification of birds, there being no change in 

 this respect from the 1886 edition. He pro- 

 ceeds to enumerate, for the benefit of this Com- 

 mittee and others, the various ' elaborate classi- 

 fications of birds ' and the various authors who 

 have written on the taxonomy of birds, not 

 omitting to mention, of course, those of Dr. 

 Shufeldt. No doubt great advances have been 

 made in the last ten years in the knowledge of 

 the structure and relationships of various 

 groups of birds ; and while many moot ques- 

 tions remain, and authorities still differ respect- 

 ing the propriety of many of the recently pro- 

 posed changes, a few points may be considered 

 as having been practically settled. While it 

 might have been well enough for the Commit- 

 tee to have expressed its opinion on some of the 

 questions thus raised, such a procedure, in 

 view of the still very unsettled state of the sub- 

 ject, seemed not particularly called for ; especi- 

 ally as there were practical difficulties in the 

 way of introducing any change in the order or 

 succession of the higher groups. 



Dr. Shufeldt strangely overlooks the main 

 purpose of the new Check List, which was not, 

 as he seems to think, the incorporation of the 

 various species and subspecies added during the 

 last ten years, and the changes of nomenclature 

 introduced during the same period, scattered 

 through half a dozen supplements to the origi- 

 nal list ; while this was important, its main 

 purpose was the revision of the matter relating 

 to the geographical distribution of the species 

 and subspecies, which the interval of ten years 

 had rendered, in many instances, not merely im- 

 perfect, but absolutely erroneous and archaic. 

 Yet this feature of the new edition seems to 



