292 The American Geologist. November, 1897 
5. Three specimens of S. profundum grown together. Beloit forma- 
tion, bed no. 5, near Monroe, Wisconsin. 
6. A longitudinal section showing large open spaces &, in the "false 
wall" a, formed by expansion of septa over a tabula; d open calycle. Ga- 
lena formation, bed no. 6, Kenyon, Minnesota. 
7. Transverse section near the apex,X 4, showing the regular arrange- 
ment of septa and open spaces left between them. Beloit formation, bed 
no. 5, Saint Paul, Minnesota. 
8. Portion of an interior cast of calycle, X2. The black lines represent 
the septa and their "striaB."' ii alar septum. Galena formation, bed 
no. 8, Mantorville, Minnesota. 
Plate XVII. 
StreptekiHvia profundum (Owen). 
1. Transverse section, X 4, of a young corallum, showing a, the sep- 
ta, 6, the theca. i, cardinal septum, ii, alar septa, x, side of the cor- 
allum that was attached to a bryozoan. The septa have been etched in 
the cell-opening and are not normal. Beloit formation, bed no. 4, St. 
Paul, Minn. 
2. Transverse section, X 4, below the tabulate portion of a corallum. 
showing the "false wall" reaching to the centre, i, cardinal, ii, alar, 
III, counter septum, h, theca partly preserved. Hudson formation, 
Richmond, Indiana. 
3. Part of a tangential thin section X 8, .s, septa, t, tabulae. Hudson 
formation, Richmond, Indiana. 
4. Part of a longitudinal thin section showing the usually thin tabu- 
lar t, and intervening septa s. Hudson formation, Richmond, Indiana. 
5. Side view of a specimen, "aS. breve.'''' Beloit formation, bed No. 
5, near Monroe, Wisconsin. 
6. View into the cell-opening of the same, i, cardinal septa, ii, alar 
septa. III, counter septum. 
7. Diagram of longitudinal median section, a, false wall, h, tabulae 
between the septa, c, free portion of the septa, d, open calycle. 
8. Side view of a small specimen, X 4. The black lines indicate the 
furrows in the theca which coincide with the septa in position and show 
the manner of increase of septa, ii, position of alar septum. Beloit 
formation, bed No. 5, St. Paul, Minn. 
9. Diagram after Kunth, to show the manner in which the septa in- 
crease in a quarter of a corallum. c. cardinal septum, a, alar septum, 
1-9 other septa. 
10. Same as the last, to show more correctly the septal increase in 
S. profundum. c, cardinal, a, alar, 1-9, other major septa, l'-9', minor 
septa. 
11. A-D. Diagrams X 5 to show the supposed order of development 
of the first septa, i, cardinal septum, A, shows 4 major septa, the pri- 
mary septa, B, shows 8 major septa, C, 8 major plus 8 minor septa, D, 8 
plus 4 major and 8 plus 4 minor septa. 
