In the spring these structures elongate into orange gelatinous protrusions or horns. They bear long fleshy protrusions (papillae) with toothless suckers at the distal portion. The lower shell is covered with hemispherical protrusions. Surfaces are rougher if they have more protrusions. Stickle bricks, using interlocking plastic protrusions, are effectively genderless. Resist holes can form in between groups of protrusions. Many fish species also have a variety of protrusions or spines on the head. The sides are ribbed with the centre either flat or having winged protrusions. The coastline forming the city's southern border is interspersed with rocky protrusions and sandy beaches. Complement coated targets are internalised by 'sinking' into the phagocyte membrane, without any protrusions. Distinctive stubby landing gear protrusions from the lower fuselage make it easily recognizable. It is a member of pentaspan transmembrane glycoproteins, which specifically localize to cellular protrusions. The trophoblasts adhere by penetrating the endometrium, with protrusions of trophoblast cells. Histopathology typically shows papillomatous protrusions and/or dysplasia. The two monomers interact notably through the two protrusions in a hugging embrace.