31. Concavities , troughs, and tubes observed on grain surfaces are the result of broken vesicle walls.32. The narrator speculates about " the mysterious emotional concavity " of her bond with her husband. 33. Towards the middle on the anterior surface the deep concavity of the nasal notch is the limiting feature. 34. Apart from a multitude of small craters, Gaspra has half a dozen large flat areas and concavities . 35. The enlarging of this open ended concavity creates a larger leeward deposition zone, furthering the process of glaciation. 36. On the graph of a function, the second derivative corresponds to the curvature or concavity of the graph. 37. The forewing and thorax are unicolorous brown while its outer margin of the hindwing has a prominent medial concavity . 38. The columella is very broad, with a gutter or concavity near to and parallel with the inner margin. 39. The purpose of the concavity in the maxilla of " F . pulvereus " is relatively unknown. 40. When the plastic is punctured, air hisses INTO the can and the concavity of the seal is reduced.