370 HYALONEMA (PHIALONEMA) PATERIFERUM. 
8 yu. Their anchors are 17-30 uw long, usually one seventh to one fourth of the 
whole spicule, 68-101 » broad, and composed of from seven to eight teeth. The 
proportion of anchor-length to anchor-breadth is 100 to 273-429, on an average 
100 : 339. The large macramphidises of form D (Plate 52, figs. 3, 4, 9, 10) are 
100-318 » long, most frequently about 200 », and have shafts 10-22 » thick, 
rarely only 8y. Their anchors are 19-47 uw long, usually one ninth to one 
seventh of the spicule, 55-122 » broad, and composed of from six to nine, usually 
eight teeth. The proportion of anchor-length to anchor-breadth is 100 to 222-420, 
on an average 100 :298. The large macramphidises of form H are mostly regu- 
lar, but irregular forms also occur among them. The regular ones (Plate 50, 
fig. 15; Plate 51, figs. 2, 17-22) are 105-265 uw long, rarely as much as 334 yp, 
most frequently about 200 u, and have shafts 14-23 » thick. Their anchors 
are 17-35 » long, usually one tenth to one seventh of the whole spicule, 62-109 
uw broad, and composed of from eight to eleven teeth. The proportion of anchor- 
length to anchor-breadth is 100 to 276-500, on an average 100 : 361. The rare 
irregular large macramphidises of this form (Plate 51, fig. 16) differ from the 
regular by their anchors being longer and composed of less numerous and spirally 
twisted teeth. The irregular large macramphidise (Plate 51, fig. 16) is 116 u 
long and has a shaft 20 » thick and anchors 42 uw long and 54 » broad. The large 
macramphidises of form F are 103-188 » long, rarely as much as 235 u. The 
frequency-curve pertaining to their length has two summits, a higher one at about 
136.5 yw, and a lower one at about 164 u. The shafts of these spicules are 11-18 u 
thick, rarely as much as 22. Their anchors are 17—30 u long, usually one eighth 
of the whole spicule, 66-105 » broad, and composed of from five to twelve teeth. 
The proportion of anchor-length to anchor-breadth is 100 to 320-430, on an 
average 100 : 363. 
The small macramphidiscs (Plate 51, fig. 15; Plate 52, figs. 5-8) are similar 
to the large ones and have, like them, a shaft which is cylindrical and of uniform 
thickness throughout (Plate 51, fig. 15) or thickened towards the ends (Plate 52, 
figs. 5, 7). The shaft is either smooth (Plate 52, fig. 6), or it bears a few low 
tubercles scattered irregularly over its central part (Plate 52, fig. 8). The 
anchors are generally one sixth to one third of the whole spicule in length, and 
composed of from four to seven teeth; in the smallest forms there are four or 
five teeth. The number of teeth in the two anchors of the same spicule is often 
different. The teeth are similar to those of the large macramphidises above 
described, but, particularly in the smallest form, more slender, relatively longer, 
and more strongly curved. 
