PLATE I. 



Figs. 1 7. SACCAMMINA CARTERI, Brady. (Page 57.) 



Fig. 1. A piece of Saccammina-limestone from Elfhills, Northumberland, 

 natural size. The upper portion of the figure shows a weathered surface, the 

 lower a fresh fracture. The white spots on the latter indicate the tufts of 

 crystals which often occupy the interior of the chambers. 



Figs. 2, 3. Detached segments. Natural size. 



Fig. 4. Polished section of fossil Molluscan Shell found by Mr. F. M. Balfour 

 on the coast about two miles and a half east of Dunbar. The interior contains a 

 string of segments of Saccammina lying in situ. Natural size. 



Fig. 5. A broken segment, showing the labyrinthic structure of the inner 

 surface of the test, and the crystalline calcareous mass occupying the interior. 

 Magnified 15 diameters. 



Fig. 6. Tangential section of the test exhibiting the arenaceous structure, 

 both of the compact exterior and of the looser labyrinthic portions. X 70 

 diam. 



Fig. 7. One of the scars, formed of a series of concentric rings, frequently seen 

 on the exterior of the segments. X 30 diam. 



Figs. 8 11. LITUOLA BENNIEANA, nov. (Page 64.) 



Figs. 8, 9. Lateral and periphero-lateral aspects. The small dark spots 

 having somewhat the appearance of perforations are embedded sand-grains of 

 nearly uniform size. The irregular depressions on the face of the large terminal 

 chamber, in fig. 9, probably represent the position and form of the pores consti- 

 tuting the general orifice. X 20 diam. 



Fig. 10. Cast of the interior of a smaller specimen. X 30 diam. 



Fig. 11. Transparent section of a small portion of the test, highly magnified, 

 illustrating the composite, arenaceous structure of the wall, and the labyrinthic 

 interior. X 100 diam. 



