Article: Some Phacopina (Trilobita) from the Silurian of Scotland

Acernaspis (Eskaspis), a new subgenus, and Podowrinella, a new genus of Phacopina.from Silurian inliers of the Midland Valley of Scotland, are here proposed. A. (Eskaspis) is restricted to the Telychian (upper Llandovery) and is referred to the subfamily Phacopinae. A. (E.) sufferta (Lament) from the M. crenulata Zone of the Pentland Hills and A. (E.) woodburnensis from the upper M. sedgwickii Zone of Girvan are described. Podowrinella, which is found in the lower Wenlock of Girvan, and in the Telychian (upper Llandovery) of the Hagshaw and Pentland Hills, can probably be assigned to the Pterygometopidae, but possesses some character states normally considered representative of Phacopidae. Coaptative structures on the ventral doublures of A. (Eskaspis) and Podowrinella are described in detail, and information is given on the auxiliary impression system on the glabella of A. (E.) sufferta.