Lower extremity of femur extended. Where the groove ceases laterally the patellar surface is seen to be continued backward as a semilunar area close to the anterior part of the intercondyloid fossa; this semilunar area articulates with the medial vertical facet of the patella in forced flexion of the knee-joint. The tibial surfaces of the condyles are convex from side to side and from before backward. Each presents a double curve, its posterior segment being an arc of a circle, its anterior, part of a cycloid. Lower extremity of femur The lower extremity of femur (or distal extremity) is the lower end of the
Tibia fusus cm (9 in.). These shells are large, spindle-shaped with moderately convex turns and an extremely long, thin and slightly curved siphonal canal. The basic color ranges from straw yellow to reddish-beige. The aperture is ovate and white inside, with 6 fingerlike growths on the outer lip. It is a fairly common species where it occurs, but because of its attractive appearance, it is highly sought after by shell collectors. Embryos develop into free-swimming planktonic marine larvae (trocophore) and later into juvenile veligers. Tibia fusus Tibia fusus, common name Spindle tibia or Shinbone Tibia Gastropod, is a species of large sea