Charles 11. Barcleen 295 



LXXXIY and CLXXXIV, length 50 mm., it is apparent in the 2d, 3d 

 and 4tli metatarsals and in the terminal phalanges of the first three toes. 

 In a cleared embryo, 6 cm. long, there are centers of ossification in all of 

 the metatarsals and torininal phalanges; in one, 8 cm. long, in the first 

 two basal phalanges as well; while in one, 10 cm. long, ossification has 

 begun in all of the metatarsals and the basal and terminal phalanges. 

 We may therefore conclude that ossification in the foot begins in the 

 three central metatarsals and in the terminal phalanx of the first toe 

 toward the end of the third month, and that it is thence extended to the 

 other metatarsals and terminal phalanges before beginning in the basal 

 phalanges. 



For a consideration of the development of the individual bones of the 

 foot reference may be made to the excellent paper of Schomburg, oo. 

 The chief points in which my observations conflict with what he describes 

 have been pointed out above. Hasselwander, 03, has recently published 

 a good account of the ossification of the bones of the foot ; and Spitzy, 03, 

 of the structure and development of the infant foot. 



SUMMARY. 



In general the development of the skeleton of the limb in man corre- 

 sponds closely with that which is known to take place in other digitates 

 and which has been recently admirably summarized by Braus, 04. Three 

 stages may be recognized, a blastemal, a chondrogenous and an osseoge- 

 nous. During the chondrogenous stage the chief features of form are 

 reached which characterize the adult structure. The centers for chondro- 

 fication correspond closely with those for ossification. The development 

 throughout is fairly direct. No distinct evidences of phylogenetic 

 structures discarded during ontogeny were found in the embryos studied. 



LITERATURE QUOTED. 



Aeby. — Die Alterverschiedenheiten der menschlichen Wirbelsaiile. Archiv. f. 



Anatomie und Physiologie, Anat. Abth., 1879, p. 77. 

 Ancel et Sexcert. — Variation numerique de la colonne vertebrale. Comptes 



rend. Assoc, des Anat. Lyon, 1901, p. 158-165. 



Les variations des segments vertebro-costaux. Bibliographic Anatom., 



X, pp. 214-239, 1902. 



Des quelques variations dans le nombre des vertebres chez rhomme. 



Journal de I'Anatomie et de la Physiologie, XXXVIII, 217-258, 1902. 

 Bade, P. — Entwickelung des menschlichen Fuss-skelets von der neunte Embry- 

 onalwoche bis ziim 18 Jahre nach Rontgenbildern. Verb. d. gesellsch. 

 deutschen Naturf. u. Aerzte 1899-1900, 463-4G6. 



Die Entwickelung des menschlichen Skelets bis zum Geburt. Archiv. 



f. mikr. Anatomie, LV, 245-290, 1900. 



