VI.-DESCEIPTION OF THE PLATES.' 
PLATE 1. 
1. The body of Springospharia verrucosa, Duncan. Natural size. 
2. A portion of the surface of the same specimen magnified to show the superficial projectionsj 
poresj and tuhulation. 
3. The top of a large emineneej with pores on its sides; the tubes are seen crowding the 
surface, and many round markings at the apex denote the openings of internal tubes. 
The specimen is the same as the last, and is more highly magnified. 
4. The body of Byringospharia monticularia, Duncan. Natural size. 
5. The same specimen magnified in part to show the monticules, pores and openings of 
tubes, with many ramifying and superficial tubes on the surface. 
6. A monticule more highly magnified to show canal openings, canals and spaces between 
them, also some small monticules. 
7. The body of a smaller and less mature specimen of Syringospkaria monticularia. 
8. A portion magnified, the radiating canals and the canal openings being shown on the 
monticules. 
9. A portion more highly magnified, showing a large monticule and smaller ones, with 
superficial tabulation and the exit of internal tubes. Pores are also shown. 
10. A part of the body of a large specimen of a mature By ring ospli aria monticularia. 
11. A portion considerably magnified, showing a minute monticule and two pores. The 
tubulation is between the dark lines, and the dots on the monticule and elsewhere are 
the openings of internal radiating tubes. 
12. A portion less highly magnified, showing numerous minute pores and larger monticules. 
