Wilder.] 



164 [April 5, 



whole, fewer than in the other, and because too, it is supported by 

 the indications of fore and hind symmetry in other parts of the 

 body" (p. 246); the objections are the same as were stated by him 

 seven years before, and relate to the thumb and great toe, which are 

 "assumed by most anatomists to be homotypes; first, on account of 

 their relative size ; second, because they have similar relative posi- 

 tions in the ordinary attitude of the fore arm ; thirdly and chiefly, 

 because they have only two phalanges each, while each of the other 

 digits has three or more" (p. 276). The first two objections to a sym- 

 metrical homology of the parts, which brings the thumb as homo- 

 logue of the little toe, are removed by showing first, that " the 

 attribute of size loses its value when studied in the lower animals " ; 

 and second, that the natural attitude of the hand is a " false posi- 

 tion " due to the "rotation of the fore arm in the embryo, but for 

 which the thumb would have been on the outside of the hand, and 

 would consequently have conformed to the position of the little toe." 

 But the third difficulty " forms the greatest in our way and is not so 

 easily disposed of; and we must rest content with the assumption that 

 the thumb with its two phalanges is the homologue of the little toe 

 with its three phalanges." (p. 277.) 



The complete removal of this difficulty is one of the chief aims of 

 the present paper, and -will be the subject of a section upon the 

 "morphical unimportance of numerical composition." 



Prof. Wyman makes a valuable suggestion (p. 274) as to the 

 normal shape of the carpal and tarsal bones, the metacarpals and 

 metatarsals (p. 275), which is capable of application to all the long 

 bones of the membra, and had been even adopted by Mivart, 46,401, 

 with respect to the scapula and ilium; if all the long bones had been 

 regarded as morphically columnar and cylindrical, the theory of 

 " torsion " would never have taken the form it did. 



Like Huxley, Wyman lays great stress upon the importance of 

 comparative anatomy and embryology in this connection, but appears 

 not to have seen the former's paper, since he does not allude to the 

 method of comparison suggested by him, namely, by placing the 

 membra parallel with each other and at right angles with the trunk, 

 the convexities of the ancon and genu looking upward as with em- 

 bryos and many lower vertebrates; and as this is the visual method 

 which now seems to me most likely to lead toward a final solution of 

 the question, the lack of allusion to it and agreement with it, appears 



