84 MATERIALS FOR A MEMOIR ON 



ZOOLOGICAL CONSIDERATIONS. 



The object which the writer has had constantly in view in 

 studying the photographs is to endeavor to determine the value 

 of attitude and gait to classification. Many of the notes bear to 

 a greater or less extent upon zoology, but a few which appear to 

 apply in an especial way to taxonomy are conveniently brought 

 together at this place. 



As is.Avell known, the manus and pes present a plan in the 

 arrangement of the elements which may conveniently receive the 

 name of the lateral and median series. In the manus, the cunei- 

 form and the unciform bones constitute the lateral, and all the re- 

 maining bones the median, series. In the pes, the calcaneum and 

 cuboid bone are embraced in the lateral series, and all the remain- 

 ing bones form the median. With this necessary understanding, 

 the writer will now proceed to state the premise upon which he 

 undertook a special examination of the manus and pes in connec- 

 tion with the phenomena of limb-movement. The episode may 

 be accepted as an instance in which tlie photographs suggest vari- 

 ous lines of 'research, even though nothing of especial value be 

 claimed for the results here secured. 



When it was determined, chiefly by the study of the stroke (see 

 p. 50), that the foot comes down by the outer border and leaves 

 by the inner, an attempt was made to ascertain by examination of 

 the structure of the carpus and tarsus the mechanism which corre- 

 lated with the movement. It was expected that an oblique line 

 by which the strain could be traced across the small bones would 

 be found. The views of Leboucq,* which embrace a path of 

 precisely this character in the embryonic form of the tarsus of 

 mammals, appeared to be confirmatory of this expectation. 



The well-known fact that the calcaneum occasionally ossifies 

 with the scaphoid bone in the human foot,t and is at times found 

 united to it by synchondrosis,^ was suggestive that the oblique 

 axis could be determined in that form with whose structure anat- 



* Arch. Biol. (Brussels), iv. 35. 



f Gruber, Mem. de I'Acad. de St. Petersbourg, ser. vii., p. 9, Taf. xvii. ; 

 Holl, Arch, fiir Klin. Chirurg., 1880; Ziickerkandl, Wiener Med. Jahrbuch, 

 1880. 



:J: Weber M., Verslag. der kon. Ak. Amsterdam, 1883, xviii. 121. 



