300 Studies of the Development of the Huiiiaii Skeleton 



vertebral bodies, the ilium, ischium, femur, tibia, fibula and of the bones of 

 the foot is represented by stippling. The last are but slightly differentiated 

 at this period. 



Plate IV. 



Figs. 7 and 8. Dorsal and plantar views of the cartilages of the left leg 

 and foot of Embryo XVII, length 18 mm. 20 cliam. 



Figs. 9 and 10. Lateral and median views of the distal portion of the right 

 half of the cartilagenous skeleton of Embryo XXII, length 20 mm. 20 diam. 



Plate V. 



Figs. 11 and 12. Median and lateral views of the distal portion of the right 

 half of the cartilagenous skeleton of Embryo CXLV, length 33 mm. 10 diam. 

 The centres of ossification of the femur, tibia and fibula are shown. 



Fig. 13. Lateral view of the left leg of an embryo 5 cm. long. 5 diam. 

 For the sake of facilitating comparison, a mirror picture has been drawn 

 and a technique has been used similar to that employed for illustrating the 

 models. The centers of ossification of the ilium, femur, tibia, fibula, the 

 three middle metatarsals and the terminal digits are shown. The position 

 of the various structures has probably been somewhat distorted during the 

 preparation of the specimen. 



Plates VI and VII. 



Figs. 14-28. Transverse sections through the twelfth thoracic and first 

 two lumbar vertebrae of a series of embryos. IJf diameters. Figs. 14-16, 

 Embryo CLXXV, length 13 mm.; Figs. 17-19, Embryo CCXVI, length 17 mm.; 

 Figs. 20-22 Embryo XXII, length 20 mm.; Figs. 23-25, Embryo XLV, length 

 28 mm.; Figs. 26-28, Embryo LXXXIV, length 50 mm. 



Plate VIII. 



Figs. 29-36. Transverse sections somewhat oblique through several ver- 

 tebrae of various embryos. 14 diam. Fig. 29, 4th sacral vertebra of Embryo 

 CIX, length 11 mm.; Figs. 30-32, 1st, 2d, and 3d sacral vertebrae of Embryo 

 X, length 20 mm.; Figs. 33 and 34, 1st and 2d sacral vertebrae of Embryo 

 CCXXVI, length 25 mm.; Fig. 35, 2d sacral vertebra of Embryo XLV, length 

 28 mm.; Fig. 36, 2d sacral vertebra of Embryo LXXXIV, length 50 mm. 



Plate IX. 



Figs. 37-40. Obliquely cut frontal sections through the sacral region of 

 several embryos. I4 diam. Fig. 37, Embryo CLXXV, length 13 mm.; Fig. 

 38, Embryo CCXVI, length 11 mm.; Fig. 39, Embryo CLXXXVIII, length 

 11 mm.; Fig. 40, Embryo LXXXVI, length 30 mm. 



Plate X. 



Figs. 41-43. Sections through the coccygeal region of several embryos. 

 IJf diam. Fig. 41, frontal section of Embryo CLXXV, length IS mm.; Fig. 

 42, sagittal section of Embryo CXLV, length 33 mm.; Fig. 43, frontal section 

 of Embryo LXXXIV, length 50 mm. 



