EXPLANATION OF PLATES IV & V, 



Illustrating Miss Johnson^s paper on the " Development of 

 the Pelvic Girdle and Hind Limb of the Chick." 



List of Reference Letters, 



II. Ilium. Is. Ischium, ph. Pubis, p. p. Pectineal process. F. Femur. 

 Cr. Crural nerves. 05. Obturator nerve. Zy. «. Iscliiatic nerves, w. Muscles. 

 TF. b. Wolffian body, m, p. Muscle plate, n. a. Neural arch. 8p. c. Spinal 

 cord. n. e. Notochord. d. a. Dorsal aorta, int. Intestine, sp. n. Spinal 

 nerve. Fb. Fibula. Fbe. Fibulare. Tb. Tibia. The, Tibiale. i, ir, iii, iv, 

 V. Skeleton of digits, pi. Processus lateralis, Ac. Acetabulum. Tar. Tar- 

 salia. 



Fig. 1. — Transverse section through hind limb and adjoining parts of five 

 days' chick ; length of whose hind limb was 0'06 inch. 



Fig. 2. — Diagrammatic longitudinal section of early six days' chick ; lengtii 

 of hind limb 0'12 in. 



Fig. 3.— Diagrammatic longitudinal section of six days' chick ; length of 

 hind limb 0'15 in. 



Fig. 4.— Diagrammatic longitudinal section of six days' chick ; length of 

 hind limb 017 in. 



Fig. 5.^Transverse section of seven days' chick. 



Fig. 6. — Diagrammatic longitudinal section of six days' chick ; length of 

 hind limb 0'2 in. 



Fig. 7. — Diagrammatic longitudinal section — more advanced stage. 



Fig. 8. — Longitudinal section through cartilages of hind limb of six days' 

 chick ; length of hind limb 0"14 in. 



Fig. 9. — ^Longitudinal section through cartilages of limb; length of limb 

 0-27 in. Eighth day. 



Fig. 10. — Single longitudinal section, in which junction of ilium and pubis 

 does not appear ; length of hind limb 0'17 in. 



Fig. 11. — Single longitudinal section, showing junction of ilium and pubis. 

 Same specimen as that from which fig. 10 was taken. 



