HYALONEMA (PRIONEMA) PINULIFUSUM. 
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1.1 times longer than the next smallest. This point lies between 62 and S4 n. 
The amphidiscs 62 /z long and shorter, that is those 15-62 /z in length, I consider 
as micramphidiscs. Some of these micrampliidiscs have relatively longer, others 
relatively shorter anchors. The relatively long-anchored are 15-35 m long, the 
relatively short-anchored 33.5-62 ^ • The length frequency-curve of the micram- 
phidiscs exhibits two marked principal elevations which correspond respectively 
to the most frequent sizes of the long- and short-anchored forms. Within the 
micramphidiscs two groups can therefore be distinguished, both from a mor- 
phological and biometrical point of view: — smaller long-anchored micramphi- 
discs, and larger short-anchored micramphidiscs. 
Of the amphidiscs 84 m long and longer, that is those 84-470 ^ in length, 
some have slender, others broad anchors. The slender-anchored are 84-380 ^ 
long, the broad-anchored 370-470 The part of the length frequency-curve 
pertaining to these amphidiscs exhibits one pronounced main elevation situated 
at about 425 n, close to its maximum end. The amphidiscs represented by this 
main elevation are all broad-anchored. These spicules form a homogeneous 
group, which I name macramphidisc because it comprises the largest amphidiscs 
of the whole series. Some of the slender-anchored amphidiscs have smooth, 
others serrated teeth. Those with smooth teeth are 84-292 m long, those with 
serrated teeth 214-380 n. Since the slender-anchored amphidiscs with serrated 
teeth are on the whole much larger than those with smooth teeth; since all the 
slender-rayed amphidiscs over 292 /z in length are serrated ones; and since the 
morphological difference of teeth serrated and teeth smooth is of considerable 
importance, I propose to consider these two kinds of slender-anchored amphidiscs 
as belonging to two distinct groups; although biometrically, judged merely by 
the length frequency-curve of the amphidiscs in general, they are not differen- 
tiated. I name these two groups, which are, in size, intermediate between the 
micramphidiscs and the macramphidiscs, smooth mesamphidiscs and serrated 
mesamphidiscs respectively. The length frequency-curve of each exhibits, 
when taken by itself, a depression, particularly well-marked in the case of the 
curve of the latter. In the curve of the smooth mesamphidiscs this depression 
lies at 121 /z , in the curve of the serrated mesamphidiscs at 260 /d. As shown 
by the two depressions of these two curves, a large and a small kind of spicule 
can be distinguished in both of them. 
The amphidiscs of Hyalonema ( Prionema ) pinulifusum can accordingly be 
arranged in seven groups : — 
