Article: Burlingiids: small proparian Cambrian trilobites of enigmatic origin
The original, and additional, specimens of Burlingia hectori are described from Canada and Sweden, B. laevis being considered synonymous with B. hectori. Westergaard's original material ol Schmalenseeia amphionura and S. acutangula is redescribed, two cranidia included with the latter being segregated as S.jagoi sp. nov. No burlingiid exoskeleton exceeds a length of 13 mm, most being less than half this size. The eye lobe was close to the glabella, the two branches of the facial suture directed outward anc forward. A large rostral plate beneath the frontal area is described, the incomplete hypostome is outlined ir one specimen; the condition may have been conterminant. The exoskeleton was non-fulcrate, the sclerite; separate but apparently flexure between them limited, lacking border and pleural furrows; lateral and posterioi doublure unknown. The pygidium of B. hectori was narrow and short; in species of Schmalenseeia the pygidium incorporated more segments, those of the thorax having been fewer. Burlingiids were world-wide in distribution, and occur in outer shelf to slope facies. They may belong with those trilobites in which the conterminant condition of the hypostome was retained throughout growth.