Histological serial sections (rostral to caudal) of the semicircular crest (LS) and uncinate process (PU) in tamarins (Saguinus spp.) across age. A–C Mid fetal S. geoffroyi (SG10) showing the LS as a ridge projecting inward from the nasal side wall (PN). The PU projects posteroventrally toward the maxilloturbinal (MT) from the LS (B, C). D–F The same spatial relationship is seen in an adult S. oedipus (So2). Note that the PU does not articulate directly with the MT (F). Abbreviations: ET I, ethmoturbinal I; LA, lamina anterior of ET I; LAP, processus anterior of the LA of ET I; SN, septum nasi. Scale bars: 0.2 mm (scale bar in A and D apply to the entire row).