BULLETIN OF THE LABORATORIES 
152 
along the middle of the stems is very evident. A similar ridge seems 
to extend along either side^ thickening the inner side of the lateral 
TOWS of cell apertures. Since the alternate arrangement of cells is 
not regular, the lower cells are often brought beneath the upper ones, 
•and then give them the appearance of having “a spur-like lip” on 
the lower side ; and again, when these specimens are not free from the 
surrounding rock they may appear to have only two or three rows of 
cells, and this same arrangement may give the false impression that 
the cells of the lateral ranges have the outer lip extended and ele- 
vated, bringing that side of the margin to a level with the inner mar- 
gin.” About 7 cells are found in a distance of 2 mm. 
Locality and position. Soldiers’ Home Quarries, Brown’s Quar- 
ry, Fair Haven, Todd’s Fork, Clinton Group. 
Genus HEMITRYPA, Phillips. 
Zoaria infundibuliform, poriferous on the inside, with branches 
nearly straight and connected at regular intervals by non-poriferous 
dissepiments. Cells in two rows, separated by a thin median keel. The 
keel is supplied with elongated tubercles above; from the columns 
thus formed, slender lateral processes extend on either side to the cen- 
tre of the space between the keels, where they are united into a deli- 
cate network, forming two series of openings between each pair of 
keels, the openings corresponding in number to the cells beneath. 
IT Hemitrypa Ulrichi, sp. n. 
{Plate XV, Fig. 2 ; Plate XVH, Fig. 2. ) 
Frond infundibuliform below, broad and horizontally expanded 
above, the edges in large specimens decumbent. Diameter of the 
largest specimen seen, 40 mm ; but fragments indicate that the speci- 
mens may attain a width of even 60 mm. 
The poriferous side rarely shown and even then the pores are usu- 
ally obscured by a peculiar network which is stretched above them. 
Branches with a median keel along the summit of which, situated at 
regular intervals, are a number of prominences from which slender 
processes extend horizontally to the centre of the space between the 
keels. The processes of adjacent branches unite along the middle of 
the space between the keels, forming a net, the circular openings of 
