82 



LJNDST110M, VISUAL OHGANN OF THE TBILOBITES. 



Pl. IV. 



Cliirurus speciosus His. p. 50. 

 Fig. 1. The riglit macnia, cast of the interiör side 12 i. 

 Specimen from Grumpevik, Vamlingbo, < rotland. 



Cybele bellatula Dalm. p. 52. 

 Fig. 2. The hypostoma :; i. Yestana. Östergötland. 



Dalmanites sclerops DALMAN p. 54. 

 Fig. 3. The hypostoma - i. 



Encrinurus punetatus \\ AHi.ENB. p. 56. 

 Fig. 4. Horizontal section of an eye ,;i1 i. Diameter 

 of the prisms 0,04 mill., their lengtli o, o? millim. 



5. The hypostoma 3 i. 



6. The left macula. Reflected light '- i. 



7. Part of the left macula in transmitted light 

 20 i. The black streaks are sectioned pores. 

 Spec. BH. 



8. Vertical section of the right macula. a sagit- 

 tal section 20 i. BH. 



'.K A similar one a along the shorter diameter 20 i. 

 Specimens 5, 6 from Vikers Boge, 4. 9 

 Medebys, Hall, 7, 8 Svarfvarehuk. All from 

 Gotland. 



Encrinurus laevis ANG. p. :>6. 

 Fig. lo. Horizontal section of the cephalic eye. 

 11. Vertical section of the same. Both 

 Prisras 0,os in breadtb, 0,06 in length. 

 cimen from Wisby. 

 12 — 17. Longitudinal profiles and anterior mar- 

 gins of the hypostomas of Encr. punetatus 

 (tigs. 12, 1.-5), F. ohtusus (tigs. 14. 15) and 

 F. hpvis (figs. 16, 17). 



Harpes vittatus Bark. p. 31. 

 The two ocelli at right s i. 

 Sagittal section of two ocelli i; " i. Specimen 

 from Lochkow E, e 2 . Bohemia. 



Homalonotus Knighti KÖNIG p. 57. 



Fig. 2n. The hypostoma ] \. ■>. 



21. The right macula, from the interiör side in 

 transmitted light - u i. From Scania. 



Illsenus chiron HOLM p. 58. 

 Fig. 22. Horizontal section of an eye. 



23. Vertical section of the same, both ,; " i. Spec. 

 AO. 



24. Hypostoma - i. Spec. AF. 



60 /l. 



Spe- 



Fig. 18. 

 19. 



25. The right macula seen in 

 The lenses translucent '- i. 

 from Persnäs, Oland. 



Illsenus Esmarki SCHLOTH. 



reflected light. 

 E\. ÅÅ. All 



p. 58. 



Fig. 26 & 27. Horizontal sections of the eyes in two 

 different specimens i; " i. 



28. Vertical section of au eye ,; " i. 



29. Likewise, '( the eye, l> a portion of the 

 cheeh 1J i. 



30. Hypostoma 2 /i. 



Fig. 31 

 32 



of the riglit macula l2 /i. Spec. 



33 



Fii 



The inside 

 AK. 



The outside of the left macula in transmitted 



light 6 %. 



Sagittal section of the macula (a) 60 /i- 



All specimens from Vestanå, Östergötland. 

 excepting tig. 3u helonging to Dr. HOLM, 

 from Ndrway, Bjerkaas. 



Illaenus gigas Holm p. 59. 

 34 & 35. Surface views of the prisms of the 

 eyes, tig. 34 at the superior margin and 35 

 at the interiör one lä /i. 



36. Cast of the inside of a hypostoma l /i. Same 

 original as Holm's fig. Tafl. I, Illsenider. 



37. Cast of the inside of the left macula. Same 



specimen '- i. 



Illaenus Roemeri Yollbortm (111. vivax Holm) p. 59. 

 Fig. 38. Hypostoma 1 /i. Spec. AO. 



39. The right macula; the lenses translucent in 

 reflected light 12 i. Spec. AO. 



40, 41. Both maculae of another, larger specimen 



12 /i. Sji. AP. From the Leptaena limestone 

 of Dalecarlia. 



Fig. 



Fig. 



42. 

 43. 



Illsenus sphaericus Holm p. 5'.». 

 The prisms of cephalic eye 12 i.) 

 The right macula 3 . transparent in^ 

 transmitted light 12 /i. Sollerön,| bpeCi ' 



ridit macula l8 /l. 



Dalecarlia. 



Lichas sp. p. 60. 



The hyiiostoma ' i. 

 Cast of the inside of the 

 Spec. T. 



Cast in wax of the preeeding 12 i. 

 47. Cast of the inside of the hypostoma. The 

 central portion with the macula' :i i. Spec. V. 

 Inside of the right macula 12 /i. Spec. V. 

 From a quarry north of the gallows near 

 Wisby. 



44. 

 45. 



46. 



4* 



Lichas latifrons ANG. ji. 00. 

 Fig. 4'.». The right macula. transmitted light, seen 

 from the inside i; " i. From Kvrkbcrget, Wisby. 



Fig. 



Fig. 



Hg. 



Platymetopus planifrons Ang. p. (i7. 



•">o. 

 51. 



52. 



54. 

 55. 



The hyiiostoma V i. 



The left macula. Transparent lensesV '- i. 

 From the Leptaena limestone of Dalecarlia. 



Trochurus pusillus ANG. p. 70. 



The hyiiostoma b /i. 



The riglit macula in transmitted light. Scen 



from the inside i; " i. From Frö.jel. 



Trochurus? p. 70. 



The hypostoma :! i. 



The riglit macula from the inside '- i. 

 From Niir, Gotland. 



