160 THE ROYAL SOCIETY OF CANADA 



The two remaining species described come from eastern Cape 

 Breton from a higher horizon. One is the carapace of a species of Euryp- 

 terid whose near allies have been found at an equivalent horizon in 

 Pennsylvania, and in England. The presence of Eurypterids, a rapidly 

 declining race, in Nova Scotia, had already been indicated by the 

 previous discovery of several fragmentary abdominal remains. The 

 other form under consideration is an odd one of doubtful relation- 

 ships, but which invites comparison with such shield bearing Meros- 

 tomata as the Xiphosurids or sword-tails. 



Phylum Charophyta 

 Genus Palaeochara 



Palaeochara n. g. — Oogonium like Chara, but with six, instead of 

 five spirally wound investing cells. Genotype Palaeochara acadica. 



Palaeochara acadica n. sp. 



Description: Oogonium subglobular to pear-shaped with hemi- 

 spherical base and conical apex. Length somewhat exceeding the 

 greatest diameter. Investing cells six in number, commencing around 

 a smooth, circular, basal area and making one complete spiral turn to 

 the raised conical end. Six or seven spiral ridges visible on a side view. 

 Length 0.55 mm.; diameter 0.53 mm.; diameter of smooth basal 

 area 0.075 mm. 



Locality: St. Rose mine, Inverness county, N.S. 



Horizon: Coal Measures. 



Remarks: The remains of the oogonium are now preserved as iron 

 pyrites, inferred to be a pseudomorph after calcite. Thin sections 

 examined under reflected light clearly show the Chara affinities of the 

 fossil in that the oogonial investment consists of partial infillings of 

 former spirally wound elongate cells. The position of the former walls 

 of these cells is revealed in section either as oblique or transverse 

 lines of parting, and in surface view by narrow grooves on the spiral 

 ridges. The latter appearance of the surface indicates that the ori- 

 ginal calcareous deposit grew from initial deposition against the 

 concave inner borders of the cells as in recent Chara. In recent Charas 

 the lateral walls break down as the fruit matures, so that a continuous 

 shell of lime finally surrounds the oospore. In Palaeochara the lateral 

 walls evidently persisted to a greater extent. The interior of the 

 oogonium is now filled with infiltrated calcite. The basal circular 

 area from which the spirals spring is a sunken pit, or foramen, and 

 probably indicates the former position of attachment of the stalk cell. 



