106 CARBONIFEROUS PERIOD. 



frequently; the stem and all tlie branches beai-ing branchlets of the usual 

 character, in regular series at each side, all of which are straight or slightly 

 curved; branches leaAdng the stem, and branchlets the stem and branches, at 

 nearly or quite unifoiTQ angles of between sixty and seventy degrees; branch- 

 lets opposite, or alternating in their arrangement, the intervals between them 

 being a little greater than the diameter of the branchlets; non-poriferous 

 side of the stem, branches, and branchlets all convex and marked by fine 

 longitudinal strife. Poriferous side of the stem and branches bearing a row 

 of pores along each of their lateral boKlers, the number of pores being 

 about twice as great as that of the branchlets, but they are not placed in 

 perfectly regular order with them. The space between these two lateral 

 rows of pores is convex, and marked by scattered dimorphous pores that are 

 not more than half as large as the principal ones which form the lateral 

 rows. Branchlets also bearing a row of pores at each lateral border of the 

 poriferous side, which are of the same character as the principal pores of 

 the stem and branches, but they average a trifle smaller than those; pore- 

 apei'tures with a rather prominent border, which gives the branchlets a 

 somewhat knotted appearance under a lens. 



There is considerable difference in the size of the broken stems and 

 branches which constitute the specimens of the collection ; but none of them, 

 not even the longest fragment, perceptibly diminishes in size toward the 

 dastal end. The largest stem is about half a millimeter in diameter and 

 the smallest not more than half that size. The branchlets vary from one 

 to three millimeters in length. The whole extent of the branching of a 

 polyzoary of this species is unknown ; but, as the branches are only exces- 

 sively developed branchlets, there seems to be no necessary restriction in this 

 regard, but, in fact, the branching seems to have been somewhat limited. 

 When one of the branchlets reached a little greater length than its fellows 

 adjacent, it sent off branchlets from its own sides and became a branch. In a 

 few cases, these first branchlets of the newly-formed branch have been seen 

 to coalesce with adjacent branchlets of the stem, thus forming a few irregu- 

 lar fenestrules. 



This species differs from G. triliniata Meek, from sti-ata of the same 

 period in Nebraska, in being much branched, and especially in the presence 



