PLATE XV. 
Tr) plasma princeps, Iith.fi] . 
Fig. 1. Portion of a highly-weathered large cylindrical corallite, showing the vertical grooves 
left by the removal of the septal lamellae, and holes by that of the septal spines. 
Tryplasma liliiformis, Eth. fit. 
Pig. 2. A typical corallite with bell-mouthed calyx, seen in natural longitudinal section. 
Fig. 3. Two corallites generally similar to Fig. 2, springing from the same parent corallite below. 
Fig. 1. Natural longitudinal section of a corallite, with unusually thick walls. 
Tryplasma dendroidea, Eth. fit. 
Fig. 5. Three young corallites, which, even at this stage, show indications of widening calices. 
Tryplasma columnaris, Eth. fit. 
Fig 6. Weathered corallite, displaying grooves left by the septal lamellre, and holes by the septal 
spines ; the edges of the tabu he are also seen. 
Tryplasma dendroidea, Eth, fit. 
Fig. 7. A typical corallite four inches long. 
