[LAMBE] SPONGES FROM COAST OF NORTHEASTERN CANADA 31 
ating the surface, principally that of the stem where they are abundant. 
1. Gastral quadriradiates.—Facial rays straight, rather slender, 
tapering to a sharp point, not in the same plane but making an angle 
with the apical ray a little less than a right angle, length about ‘104 
mm., thickness at midlength ‘003 mm.; apical ray straight, sharply 
pointed, averaging in length ‘065 mm. and in thickness ‘0049 mm. 
2. T'ubar triradiates.—Sagittal ; all rays of the same thickness and 
rather slender; lateral rays nearly at right angles to and curved slightly 
toward the basal ray, about ‘078 mm. long and ‘005 mm. in diameter 
at midlength; basal ray about ‘163 mm. in average length, tapering 
gradually to a fine point. 
3. Dermal triradiates.—Sagittal; varying considerably in size and 
in the proportionate length of the basal ray. The lateral rays are 
oblique to and make an angle of about 25° with the plane in which the 
basal ray lies. All the rays are of equal thickness, the basal ray is 
straight and tapers to a point, reaching a length of ‘232 mm. with a 
diameter at midlength of ‘010 mm., the lateral rays are also sharply 
pointed, generally straight, with a length of about ‘191 mm. and an 
included oral angle of about 115°. The basal ray is at times equal in 
size to or not much longer than the lateral rays. 
With the dermal triradiates may be classed the triradiates that com- 
pose the stem. These latter are very similar in shape to the dermal 
triradiates and both forms pass by insensible gradations the one into the 
other, the principal differences being that the spicules of the stem have 
a somewhat larger basal ray and) shorter lateral rays with an oral angle 
of 145°; the basal ray reaches a length of ‘262 mm., the lateral rays are 
about ‘072 mm. in length with a diameter at midlength of ‘010 mm. 
and curve a little toward the basal ray. The dermal triradiates with 
those of the stem have the basal ray directed downward and the lateral 
rays inclined inward. 
4. Slender oxea of the stem.—Occurring abundantly in the stem, at 
right angles to and projecting beyond the surface; slightly curved, 
sharply pointed, about ‘078 by ‘002 mm. in size. This spicule is found 
only in small numbers in the head. 
Locality.—Davis Strait, Cape Aston, 60 fathoms, Captain Phillips, 
10th of August, 1891. 
