232 TRANS. OF THE ACAD. OF SCIENCE. 
Fenestrules long, irregular in form, generally quadrangular, 
seven or eight times as long as the width of the interstices, 
deeply indented or knotted on the sides by large and project- 
ing cells; two and one-half in the space of two lines vertical- 
ly, about four in two lines transversely. 
C e and prominent, distant, placed i in somewhat va- 
ried series on the two sides of the longitudinal ribs, alterna, 
six or eight to each fenestrule. 
species resembles no other which I haye seen describ: 
ed; it has been described from a fragment well preserved on 
the surface of a black limestone, with other more imperfee 
branches embedded in the matrix; the stems are sometimes 
slender, and become irregularly thickened near the bifurea- 
tions, where they have the indistinct appearance of another 
| Pasesonina Suumarpu. (Prout.) — 
