PLATE XXIV. 
Figs. 1, la . — Sertularia filiformis [gracilis] 1 (p. 51). 
Fig. 1. — A colony; natural size. 
Fig. la. — Portion of a colony ; magnified 15 diameters. 
Figs. 2, 2a. — Sertularia annulata (p. 52). 
Fig. 2. — A colony; natural size. 
Fig. 2a. — Portion of a colony; magnified 15 diameters. 
1 It has been found necessary to change the name since the plate was printed off. 
