Fig. 44. The hypostoma 1/1. » 45. Cast of the inside of the right macula 12/1. Spec. T. » 46. Cast in wax of the preceding 12/1. » 47. Cast of the inside of the hypostoma. The central portion with the maculæ 3/1. Spec. V. » 48. Inside of the right macula 12/1. Spec. Y. From a quarry north of the gallows near Wisby. =Lichas latifrons= ANG. p. 60. Fig. 49. The right macula, transmitted light, seen from the inside 60/1. From Kyrkberget, Wisby. =Platymetopus planifrons= ANG. p. 67. Fig. 50. The hypostoma 1/1. » 51. The left macula. Transparent lenses? 12/1. From the Leptæna limestone of Dalecarlia. =Trochurus pusillus= ANG. p. 70. Fig. 52. The hypostoma 5/1. » 53. The right macula in transmitted light. Seen from the inside 60/1. From Fröjel. =Trochurus?= p. 70. Fig. 54. The hypostoma 3/1. » 55. The right macula from the inside 12/1. From När Gotland. K. Sv. Vet. Akad. Handl., Bd 34, No 8. Lindström: Trilobites. IV. [Illustration] G. Liljevall del. Ljustryck af Chr. Westphal Stockholm. Pl. V. =Megalaspis attenuata= WAHLENB. Fig. 1. Horizontal section of cephalic eye near the inferior margin 60/1. _a_ surface of the eye, _b_ frame with irregular or reserve prisms, _c_ part of the cheek with normal structure. Spec. DP. » 2. Hypostoma 2/1. Spec. BM. » 3. The right macula 12/1. » 4. Part of the same in transmitted light 60/1. Spec. DR. » 5. Vertical (sagittal) section of the inferior part of the hypostoma, crossing the macula _a_ 12/1. » 6. Vertical section of the same macula 60/1. All spec. from Westanå, Östergötland. =Megalaspis limbata= BOECK p. 61. Fig. 7. Hypostoma, mostly decorticated 2/1. Specimen from Fogelsång, Scania, the same as BRÖGGER'S original to his fig. 23. =Megalaspis planilimbata= ANGEL. p. 61. Fig. 8. Hypostoma, Öland, Äleklinta 2/1. =Megalaspis= sp. Fig. 9. Vertical section of macula (_a_) 12/1. Öland, Lower grey Orthoc. limestone. =Nileus armadillo= DALM. p. 62. Fig. 10. Horizontal section of cephalic eye 60/1. » 11. Vertical section of the same 60/1. » 12. A similar section 60/1. _a_ the prisms of clear calcareous spar, _b_ the surface of the eye and the free cheek of yellow spar. » 13. The hypostoma 2/1. » 14. The right macula 12/1. » 15. Vertical section of macula (_a_) 12/1. All specimens from Persnäs, Öland, excepting fig. 13 from Westanå, Östergötland. =Symphysurus palpebrosus= DALMAN p. 62. Fig. 16. Horizontal section of cephalic eye 60/1. » 17. Vertical section of the same 60/1. » 18. Hypostoma 2/1. From Westanå, Östergötland.