SPONGES, GRAPTOLITES, CORALS. 75 
Rauffella.] 
Family DICT YOSPONGIDA®, Hatt. 
RAUFFELLA, Ulvich. 
PLATE F, FIGS. 16-20. 
1889. Rauffella, ULR1cu. American Geologist, vol. iii, p. 235. 
Original description.“ Sponges free (?) forming hollow cylindrical stems, or 
radially arranged leaves. Wall exceedingly thin, composed of two distinct layers of 
spicule-tissue. Inner layer minutely porous, the pores irregularly distributed, of 
unequal size, the larger ones rounded, the smaller ones much more numerous and 
mostly of irregularly angular outline ; spicular tissue separating pores thin, the nature 
of its elements undetermined. Outer layer consisting of a network of large spicules, 
apparently of a curiously modified hexactinellid type. Usually they appear as 
irregularly coalescing thread-like striz lining the surface im a longitudinal direction, 
with more slender connecting filaments traversing the narrow intervening spaces at 
more or less acute angles, leaving acutely elliptical depressed spaces. At other times 
the strizw cross each other diagonally, producing an appearance not much unlike that 
of the ordinary arrangement of the spicules in the Dictyospongidw. 
“Type R. filosa Ulrich.” 
RavuFFetyia FILOSA Ulrich. 
PLATE F, FIGS. 16-18. 
1889. Rauffella filosa ULRIcH. American Geologist, vol. iii, p. 237, figs. 1, 2, 4. 
Original description—‘Sponge forming a straight or slightly curved hollow 
cylindrical stem, 10 to 15 mm. in diameter. The largest fragment seen is 90 mm. in 
length. One of the ends (whether the upper or lower one, has not been determined) 
is rounded off somewhat like the tip of a finger. The other, probably, was open. 
Sponge wall less than 0.5 mm. in thickness. Outer surface generally appearing to 
the naked eye as stiongly striated longitudinally. Under a good pocket lens numer- 
ous connecting filaments are noticeable forming with the stronger threads an irregu- 
lar, narrow-meshed net-work. Nearly every specimen, however, exhibits on limited 
portions of the surface a comparatively regular arrangement of the spicular tissue 
in diagonally intersecting lines. Here the hexactinellid character of the spicules 
is determined, there being, apparently, four rays spread horizontally and one extend- 
ing downward into the inner tissue, while the sixth is not developed. The spicules 
are joined together by a union of the horizontal rays of each with those of four 
