242 
HYALONEMA (HYALONEMA) GRANDANCORA. 
250 n] thickness of shaft 13 n; diameter of central tyle 15 n; spines of central 
tyle 7 m long and 6 u thick; anchors 74 n long and 110 n broad. 
The large micramphidiscs (Plate 79 , figs. 24, 25) are 37-80 n long, most 
frequently about 43, 55, and 70 n } The shaft is straight, 2-3.5 n thick, and 
somewhat gradually thickened in or near the middle to a stout, often rather 
irregular, and not very clearly defined central tyle, 3-6 m in transverse diameter, 
that is 1.5-3. 5 n more than the adjacent parts of the shaft. The tyle and the 
remaining parts of the shaft are quite densely covered with small, slender spines. 
The spines on the tyle are scattered, not arranged in a verticil. 
The terminal anchors are 12-29 n long, usually a little more than a third of 
the whole spicule, and 10.5-26 n broad. The proportion of anchor-length to 
anchor-breadth is 100 to 75-100, on an average 100 : 86.3. The individual 
anchor-teeth are strongly curved in their proximal parts and only slightly curved 
or nearly straight in their distal and middle-parts. Their ends generally diverge 
rather considerably from the axis of the shaft. 
The small micramphidiscs (Plate 79 , figs. 3-11) are 17-31 n long, most 
frequently about 23.3 n. The shaft is generally straight, rarely bent in the 
middle, is 1.3-1. 6 n thick, and in the larger forms often slightly and gradually 
thickened in or near the middle, in the smaller generally of uniform thickness 
throughout. The shaft is quite densely covered with small slender spines. 
The terminal anchors are 4-13 n long, a quarter to a third of the whole 
spicule, and 6-14 n broad. The proportion of anchor-length to anchor-breadth 
is 100 to 85-140, on an average 100 : 123. The anchor-teeth are curved more 
strongly in their basal than in their distal part. Their ends are parallel or 
nearly so. 
The species is very well characterized by the large size and the great relative 
breadth of the anchors of its macramphidiscs. The only species which has 
similar macramphidiscs and pinules is Hyalonema ( Prionema ) agujanum described 
in this Report. From this it is distinguished by the large and slender amphi- 
discs with serrated teeth which are exceedingly abundant in H. ( P .) agujanum 
and absent in H. ( H .) granclancora. 
1 Their length frequency-curve has three distinct elevations corresponding to these sizes. 
