Figure 87. Right side view of same bonito hook shanks as those in figure 86, posterior longitudinal convexity corresponds to outer curve of shell, front concavity increased by inner projection of hinge which forms head, points in position to indicate how tail grooves cut after fitting point against shank: a, shank with normal-sized head, head is 12 mm. thick, tail is 4 mm. thick, middle thickness is 6 mm.; b, large thick shank with exaggerated head well ground down to reduce its thickness, head is 16 mm. thick, tail is 4 mm. thick, middle thickness is 6 mm.; c, thin shank with marked small head, head is 8 mm. thick, tail is 2 mm. thick, middle thickness is 4 mm.; d, long shank with rough irregular small head from outer section of hinge, head is 11 mm. thick, tail is 3 mm. thick, middle thickness is 4 mm.; e, shank with small head, pronounced longitudinal curve, point with three holes only two of which necessitate cutting of grooves for lashing, head is 10 mm. thick, tail is 3 mm. thick, middle thickness is 5 mm. 1, head; 2, tail; 3, head point; 4, mesial edge; 5, head hole; 7, antero-lateral surfaces of head; 8, distal triangular surface on head; 9, tail grooves made after fitting point; 10, sides of shank, continuous with antero-lateral surfaces of head; 11, point.