Fig. 16. The hypostoma 3/1. » 16. The right macula 12/1. » 17. Horizontal section of the cephalic eye 60/1. » 18. Vertical section of the cephalic eye, _a_ cheek 60/1. Probably from the Carbon of Belgium. =Proetus concinnus= DALM. p. 67. Fig. 19. Horizontal section of the cephalic eye, a little oblique, at right the innermost stratum with the rock 60/1. » 20. Vertical section of the cephalic eye. The diameter of the prisms 0,03 millim. » 21. Hypostoma 4/1. » 22. The right macula 12/1. » 23. The same with a light, transparent spot 12/1. Specimen from Djupvik, Eksta. =Proetus conspersus= ANG. p. 68. Fig. 24. A portion of the cephalic eye 20/1. » 25. The hypostoma. Cast of the interior side 4/1. » 26. Cast of the interior side of the left macula 12/1. Fig. 24 from Öja, Gotland, the others from Kräklingbo. =Proetus signatus= LDM. p. 68. Fig. 27. Hypostoma 4/1. » 28-30. Three pair of maculæ with dark ocelli in a white spot. =Ptychopyge angustifrons= DALM. p. 69. Fig. 31. Horizontal section of the cephalic eye 250/1. » 32. Hypostoma, a broad variety 1/1. » 33. Another, a narrow variety 1/1. » 34. The left macula of the hypostoma fig. 32 4/1. » 35. A similar of the narrow variety 4/1. » 36. Vertical section of a macula. _a_ the macula 20/1. Specimens from Vestanå and Kungs Norrby, Östergötland. =Ptychopyge cincta= BRÖGGER p. 69 (according to FR. SCHMIDT. The figure 12 _a_ of BRÖGGER resembles, however, the hypostoma of Pt. angustifrons, but not the hypostomata which have been prepared from the Ptych. cincta). Fig. 37. A hypostoma; the maculæ are directed obliquely 2/1. » 38. The right macula of another specimen 4/1. » 39. Vertical section of a macula 60/1. Specimens from Kungs Norrby, Östergötland. =Ptychopyge aciculata= ANG. p. 68. (Compare BRÖGGER II Taf. I, fig. 13.) Fig. 40. The hypostoma, cast of the interior surface 1/1. » 41. Cast of the right macula 4/1. Specimen from Öland, Brunsby. =Ptychopyge glabrata= ANG. p. 69. Fig. 42. Original of BRÖGGER'S fig. 14. Cast of the inside of the right macula 4/1. Ǎlleberg. =Elyx laticeps= ANG. p. 19. Fig. 43. The interior surface of the right fixed cheek and the glabella. Magnified. Specimen from Andrarum. 4/1. =Conocoryphe= p. 19. Fig. 44. Cast of the interior surface of the left cheek. Magnified. From Andrarum. 4/1. =Solenopleura brachymetopa= ANGEL. p. 19. Fig. 45. The head shield, cast of the interior surface. Magnified. Specimen from Andrarum, Scania. 4/1. =Apus cancriformis= SCHÄFFER p. 73.