Here is a detailed look at the evolution of each Marx figure (US Only right now). The body and components of each figure was far from fixed. Many changes ocurred for each figure over the 'Johnny Decade' (1965-1975).

Before you begin the tour, we need to establish a common name for the various body parts. This pictorial series shows a line drawing of the part, a name and a brief description (Click on the image to enlarge it):

Skip Part Definitions and see how each figure was modified...

Body Parts

Element	Description
Pins and Rivets	Clevis Pin A one piece metal pin that has a rounded head (like a nail head) and the other end has been flattened with a hole machined into the center of this flattend area. The shoulder and hip clevis pins were the same length. Rivets A one piece metal pin (also known as a tubular rivet) that has a rounded head (like a nail head) and the other end is hollow. The parts would be assembled with this rivet and a press would flare out the hollow end - joining the parts together. The Elbow and Knee rivets are different lengths on each figure.
Springs	2 Part Shoulder Spring The 2 Part Spring is a low tension spring. On one end, a normal loop is formed from the end of the spring coil. On the other end the last few coils are more tightly wrapped and taper to a point. A second piece of spring wire is shaped into a hook and inserted into this taper and held in by twisting its end upon itself. This allows the two spring ends to rotate independently of each other. 1 Part Easy Pull Spring The 1 Part Spring came into use when the figures went to the Clevis Pin design. Since the clevis pins could rotate in the shoulder is was no longer necessary for the spring ends to rotate independently also. It is called 'Easy' pull in relation to the next spring that was used in 1974 that was much stronger. 1 Part Hard Pull Spring The 1 Part Spring came into use in 1973-74 with the introduction of the BOTW series. It is called 'Hard' pull in relation to the previous spring that was much weaker. Normally collectors dislike this spring as it is so strong that on vintage figures it will actually pull the shoulders together with so much force that the shoulders on the torso split. Most collectors will replace this spring with a modern substitute or a vintage weaker spring to avoid damage. Always keep the hard pull spring with the figure to maintain its provenance. Hip - Attached Spring (Spring Perch) This type of hip/spring combination is only found in the right hip of pre 1969 figures. Commonly called a 'Spring Perch', this hip is molded with a hole though the center. A rivet is then inserted and a strong spring is 'permanently' attached to the rivet. The spring has one end that is very tightly coiled that wraps around the rivet shaft, a washer is then placed over the shaft and the end of the shaft is then flared - holding the assembly in place. This Spring Perch assembly was ended when Marx went to the Clevis pin design. The right hip was then 'cupped', like the left hip and a Clevis pin was used with a separate hip spring. Hip Spring This spring was used after the Perch Spring. Different figure types (Adult Male, Jane, Princess Wildflower, Kids) used different sizes but the basic construction was the same
Shoulders	Shoulder - Plastic Loop This type of shoulder is molded in one piece (upper arm) and contains a loop of plastic with a hole molded in to accept the spring end. This design only lasted a short time (perhaps less than a year) as the hole can be easily damaged by the shoulder spring during assembly or play. Shoulder - Plastic Loop with Groove This type of shoulder is molded in one piece (upper arm) and contains a loop of plastic with a hole molded in to accept the spring end. On the 'ball' of the shoulder a shallow groove or trench runs across the ball up to or underneath the plastic loop. This groove was likely added to ease the assembly process, but again, only lasted a short time. Shoulder - Reinforced Plastic Loop This type of shoulder is molded in one piece (upper arm) and contains a loop of plastic with a hole molded in to accept the spring end. In the hole a metal eyelet has been fitted to reinforce the plastic of the loop. This solved the problem of the spring end eventually cutting through the loop. Shoulder - Reinforced Plastic Loop with Groove This type of shoulder is molded in one piece (upper arm) and contains a loop of plastic with a hole molded in to accept the spring end. In the hole a metal eyelet has been fitted to reinforce the plastic of the loop. It was determined that the spring end would eventually cut through the loop. On the 'ball' of the shoulder a shallow groove or trench runs across the ball up to or underneath the plastic loop again, likely to ease assembly. Shoulder - Clevis Pin This type of shoulder is molded in one piece (upper arm). On the inside of the shoulder it is partially hollow creating a 'cup'. A hole is molded in the shoulder. The clevis pin is pushed into this hole and its business end is encased in this cup. The spring is then attached to the hole in the pin. Shoulder - Clevis Pin with Groove This type of shoulder is molded in one piece (upper arm). On the inside of the shoulder it is partially hollow creating a 'cup'. A hole is molded in the shoulder. The clevis pin is pushed into this hole and its business end is encased in this cup. The spring is then attached to the hole in the pin. The edge of this cup has been notched to allow the spring to be more easily attached to the pin.
Hips	Hip - Attached Spring (Spring Perch) This type of hip/spring combination is only found in the right hip of pre 1969 figures. Commonly called a 'Spring Perch', this hip is molded with a hole though the center. A rivet is then inserted and a strong spring is 'permanently' attached to the rivet. The spring has one end that is very tightly coiled that wraps around the rivet shaft, a washer is then placed over the shaft and the end of the shaft is then flared - holding the assembly in place. This Spring Perch assembly was ended when Marx went to the Clevis pin design. The right hip was then 'cupped', like the left hip and a Clevis pin was used with a separate hip spring. Hip - Plastic Loop This type of hip is molded in one piece (upper thigh) and contains a loop of plastic with a hole molded in to accept the spring end. Hip - Plastic Loop with Groove This type of hip is molded in one piece (upper thigh) and contains a loop of plastic with a hole molded in to accept the spring end. On the 'ball' of the hip a shallow groove or trench runs across the ball up to or underneath the plastic loop. Again, likely to aid in assembly. Hip - Reinforced Plastic Loop This type of hip is molded in one piece (upper thigh) and contains a loop of plastic with a hole molded in to accept the spring end. In the hole, a metal eyelet has been fitted to reinforce the plastic of the loop. It was determined that the spring end would eventually cut through the loop. Hip - Reinforced Plastic Loop with Groove This type of hip is molded in one piece (upper thigh) and contains a loop of plastic with a hole molded in to accept the spring end. In the hole a metal eyelet has been fitted to reinforce the plastic of the loop. It was determined that the spring end would eventually cut through the loop. On the 'ball' of the hip a shallow groove or trench runs across the ball up to or underneath the plastic loop. Hip - Clevis Pin This type of hip is molded in one piece (upper thigh). On the inside of the hip it is partially hollow creating a 'cup'. A hole is molded in the hip. The clevis pin is pushed into this hole and its business end is encased in this cup. The spring is then attached to the hole in the pin. Hip - Clevis Pin with Groove This type of hip is molded in one piece (upper thigh). On the inside of the hip it is partially hollow creating a 'cup'. A hole is molded in the shoulder. The clevis pin is pushed into this hole and its business end is encased in this cup. The spring is then attached to the hole in the pin. The edge of this cup has been notched to allow the spring to be more easily attached to the pin.
Torso	Torso - No Stop Bar This type of torso is molded in one piece. The hip socket is sometimes molded with 'ribs' that inhibit the free twirling of the leg. But this design allows the top of the hip to 'slip inside' of the torso hole making the leg splay out at an exaggerated angle. Torso - With Stop Bar This type of torso is molded in one piece. On the inside of the hip hole, you can see a piece of plastic that is centered in the hole, at the top. This 'Stop Bar' was a mold modification to prevent the top part of the leg from slipping inside the torso causing the figure to fall down or "do the splits". Not all molds were modified this way.