The Diatomaceæ of Philadelphia and Vicinity

PLATE 4

Reading edition

Fig. Page ACTINOPTYCHUS 1-4-6 Actinoptychus undulatus (Kuetz.) Ralfs. 24 2 Actinoptychus undulatus (inner stratum) 24 3 Actinoptychus heliopelta Grun. var.? 25 5 Actinoptychus vulgaris var. interrupta n. var. 24 POLYMYXUS 7 Polymyxus coronalis L. W. Bail. 25 AULACODISCUS 8 Aulacodiscus argus (Ehr.) A. S. 26

Illustration from The Diatomaceæ of Philadelphia and Vicinity

Fig. Page

ACTINOPTYCHUS

1-4-6 Actinoptychus undulatus (Kuetz.) Ralfs. 24

2 Actinoptychus undulatus (inner stratum) 24

3 Actinoptychus heliopelta Grun. var.? 25

5 Actinoptychus vulgaris var. interrupta n. var. 24

POLYMYXUS

7 Polymyxus coronalis L. W. Bail. 25

AULACODISCUS

8 Aulacodiscus argus (Ehr.) A. S. 26