Redescription of the Trilobite Eoharpes Raymond, 1905

Abstract

From Dr. Archie Lamont :— Following Bancroft's example in dealing with Cryptolithinae, I have for some time considered applying a fringe-character classification to harpids. On this basis, in a manuscript prepared in 1947 I distinguished by name four apparently natural families : (1) with pits of fairly uniform size as in Eoharpes primus (Barrande); (2) with outer rows of larger pits grading into a finer inner pit complex as in Metaharpes amibouéi Lamont; 1 (3) with an outer row of large pits and inner complex of fine pits, but no gradation between the two, as in Scotoharpes domina Lamont; 2 and (4) Harpidae which show a combination of the characters of (2) and (3), as in Harpes macrocephalus Goldfuss. 3 Observations have also been made on the use of facial sutures in classification of Harpacea. In Scotoharpes domina a longitudinal suture has been described which meets a lateral transverse suture on the ala. This suggests a primitive arrangement whereby the longitudinal suture may have corresponded with the boundary between axial and pleural lobes and the lateral suture with the division between the anterior part of the cephalon and the occipital segment. If this is true, it seems likely that in Proparia the lateral suture is preserved, but in Opisthoparia the longitudinal suture only. In " Harpes " flanaganni (Portlock) (Hunterian Museum, Glasgow University, A.40), what seems to be a sensory tubercle occurs in the axial furrow, and from it a narrow suture runs outwards across the posterior half of the ala.