Fig. 10. Horizontal section of the cephalic eye. » 11. Vertical section of the same. Both 60/1. Prisms 0,05 in breadth, 0,06 in length. Specimen from Wisby. » 12-17. Longitudinal profiles and anterior margins of the hypostomas of Encr. punctatus (figs. 12, 13), E. obtusus (figs. 14, 15) and E. lævis (figs. 16, 17). =Harpes vittatus= BARR. p. 31. Fig. 18. The two ocelli at right 8/1. » 19. Sagittal Section of two ocelli 60/1. Specimen from Lochkow E, e^2, Bohemia. =Homalonotus Knighti= KÖNIG p. 57. Fig. 20. The hypostoma 3/2. » 21. The right macula, from the interior side in transmitted light 20/1. From Scania. =Illænus chiron= HOLM p. 58. Fig. 22. Horizontal Section of an eye. » 23. Vertical section of the same, both 60/1. Spec. AG. » 24. Hypostoma 2/1. Spec. AF. » 25. The right macula seen in reflected light. The lenses translucent 12/1. Ex. AA. All from Persnäs, Öland. =Illænus Esmarki= SCHLOTH. p. 511. Fig. 26 & 27. Horizontal sections of the eyes in two different specimens 60/1. » 28. Vertical section of an eye 60/1. » 29. Likewise, _a_ the eye, _b_ a portion of the cheek 12/1. » 30. Hypostoma 2/1. » 31. The inside of the right macula 12/1. Spec. AR. » 32. The outside of the left macula in transmitted light 60/1. » 33. Sagittal section of the macula (_a_) 60/1. All specimens from Vestanå, Östergötland, excepting fig. 30 belonging to Dr. HOLM, from Norway, Bjerkaas. =Illænus gigas= HOLM P. 59. Fig. 34 & 35. Surface views of the prisms of the eyes, fig. 34 at the superior margin and 35 at the inferior one 12/1. » 36. Cast of the inside of a hypostoma 1/1. Same original as HOLM'S fig. 6 Tafl. I, Illænider. » 37. Cast of the inside of the left macula. Same specimen 12/1. =Illænus Roemeri= VOLLBORTH (Ill. vivax HOLM) p. 59. Fig. 38. Hypostoma 1/1. Spec. AO. » 39. The right macula; the lenses translucent in reflected light 12/1. Spec. AO. » 40, 41. Both maculæ of another, larger specimen 12/1. Sp. AP. From the Leptæna limestone of Dalecarlia. =Illænus sphæricus= HOLM p. 59. Fig. 42. The prisms of cephalic eye 12/1. } » 43. The right maculæ, transparent in } transmitted light 12/1. Sollerön, } Spec. AH. Dalecarlia. } =Lichas= sp. p. 60.