Franklin P. Mall AD 
Ischium.—This nucleus appears first on the 105th day in the body of 
the ischium. It is one millimeter in diameter in embryo R. 
Calcaneum (variation).—A nucleus one millimeter in diameter is in 
the middle of of this bone on both sides on the 65th day. It is not pres- 
ent in any of the older embryos. 
Metatarsal bone-—The second metatarsal bone is the first of this row 
to appear and is present as a small nucleus in an embryo 58 days old. 
In an embryo 60 days old the second, third and fourth metatarsal bones 
have begun to ossify and in a second embryo 58 days old all five bones 
Fic. 6. Foot of embryo No. 300 (73 mm. long), enlarged 3 diameters. 
are present, the second being the largest. On the 75th day they are 
about one, and on the 90th day about two millimeters long. 
My data correspond in time with those given by Quain, who states that 
the metatarsal ossify in the 8th or 9th week. Other anatomists find the 
time of their appearance all the way from 6 weeks (Gegenbaur) to 5 
months (Schwegel). Hasselwander,” who has made an exhaustive study 
of the ossification of the bones of the foot, fixes the time of the appear- 
1° Hasselwander, Zeit. f. Morph. u. Anthropol., 5, 1903. 
