HYALONEMA (OONEMA) BIANCHORATUM PINULINA. 
323 
of specimen 
a 
of specimen 
b 
of both speci- 
mens together 
Length n 
limits 
220-480 
212-492 
212-492 
most frequently about 
240, 320, 468 
277, 387, 468 
468 
Shaft, thickness, limits n 
17-26 
19-28 
17-28 
Central 
tyle 
transverse diameter of tyle, n limits 
* 17-31 
19-32 
17-32 
the tyle thicker than the shaft by ,u, 
limits 
• 0-8 
0-9 
0-9 
length, limits ^ 
90-122 
94-140 
90-140 
breadth, limits £i 
148-195 
140-210 
140-210 
Terminal 
proportion of anch- 
or-length to anchor- 
breadth 
limits 100 to 
141-177 
131-189 
131-189 
anchors 
average 100 to 
161.4 
158.6 
160.1 
proportion of anch- 
or-length to total 
length of whole spi- 
cule 
limits 1 : 
2. 1-3.9 
average 1: 
3.2 
a stout knob or two are observed also on other parts of the shaft (Plate 85 , 
figs. 1, 2). The single large spine on the central tyle is, in the normal large 
macramphidiscs, sometimes 21 n long and 14 n thick. I have never seen more 
than one such large spine on a normal spicule of this kind. In a few abnormal 
large macramphidiscs I observed (Plate 85 , fig. 3) one or two clusters of verticils 
of projections arising some distance from the middle of the shaft. These had a 
maximum length of 45 ix, and were inclined or curved towards the centrum. 
They appear to be supernumerary anchor-teeth. 
The proportion of the terminal anchor to the total length of the whole spicule 
is (in both specimens together), as stated above, 1 to 2. 1-3.9, an average of 1 : 3.2. 
The difference between total length and anchor-length is the greater the larger 
the spicule. In the large macramphidiscs 400 p and more in length the above 
proportion is 1 : 3. 2-3. 9, in those under 300 p in length 1 : 2.1-3. 
The anchor-teeth are about 30 n broad and pointed at the end. They arise 
nearly vertically from the shaft and are quite strongly curved in their proximal, 
and straight in their distal part. Their total curvature is such that their end- 
parts diverge at an angle of 12°-22° from the shaft. 
The chief dimensions of the s?nall macramphidiscs (Plate 83 , fig. 45c; 
Plate 84 , figs. 3-13, 26-32) are: — 
