Charles R. Bardeen Sula 
which are united for a longer distance are separated by commas. In 
several instances the femoral nerve divided into two main divisions before 
separating into branches. These are shown in part B of the table. 
II. OBTURATOR GROUP. 
a. Embryon¢ Development. 
1. General Features. 
In an embryo 11 mm. long (Plate III, Fig. 1), the obturator nerve 
passes about the pelvic blastema between the pubic and ischial process 
and terminates some distance beyond in several branches. Differentia- 
tion of musculature is beginning in the region about the terminus of 
the nerve. One branch of the nerve terminates in a mass of tissue which 
represents the anlage of the obturator portion of the M. adductor mag- 
nus, and possibly also the M. obturator externus. The main nerve trunk 
then breaks up into several short branches about which hes a mass of 
tissue representing the anlage of the adductor longus and brevis and 
the gracilis muscles 
In an embryo of 14 mm. (Plate VIII, Fig. 1) the individual muscles 
may be clearly recognized. None of them have well developed tendons. 
The figure represents sufficiently well the relations of the adductor 
muscles at the period under consideration. The gracilis muscle is merely 
outlined in order to show the short and long abductors. Each muscle is 
separated from its neighbors by a loose connective tissue. In this tissue 
the nerves take their course to the muscles. The nerve to each muscle 
strikes it about the center of greatest development, and may extend into 
the muscle substance for some distance. The paths for this intramuscu- 
lar nerve growth are not in all cases clearly marked. In older embryos 
they are much plainer. The obturator and sciatic portions of the ad- 
ductor magnus muscle are distinctly separate. See also Plate II, Fig. 3. 
In an embryo of 20 mm. (Plate VIII, Fig. 2) the muscles have all 
become attached by tendons to the skeleton. Merely the origins and 
attachments of the adductor brevis and gracilis muscles are shown in 
Fig. 2. Figs. a and b represent the gracilis and adductor brevis muscles 
seen from the deep surface. The obturator and sciatic portions of the 
adductor magnus muscle have become fused. 
In slightly older embryos the muscles become much more separated by 
relatively great development of intermuscular connective tissue than is 
found in late foetal life and after birth. Compare Figs. 2, 3, and 4, 
Plate II, with figures of frozen sections of the adult limb. 
