PLATE XXIX. 
Figs. 1, la. — Sertularia cylindritheca (p. 59). 
Fig. 1. — Portion of a colony ; natural size. 
Fig. la. — Portion of same ; magnified 10 diameters. 
Figs. 2, 2 u. — Sertularia integritheca (p. 60). 
Fig. 2. — A colony ; natural size. 
Fig. 2 a. — Portion of a colony; magnified 10 diameters. 
Figs. 3, 3 a. — Sertularia articulata (p. 61). 
Fig. 3. — Portion of a colony ; natural size. 
Fig. 3 a. — Portion of same ; magnified 20 diameters. 
