286 . ARACHNIDA—EURYPTERIDA CHAP. 
Fic. 162.—2Hurypterus fischeri, Eichw. Upper Silurian, Rootzikiill, Oesel. Restoration 
of ventral surface ; 1-6, appendages of prosoma ; m, metastoma. Immediately pos- 
terior to the metastoma is the “median process”’ of the genital operculum. (After 
Holm. ) 
