HYALONEMA (PRIONEMA) FIMBRIATUM. 
301 
Occasionally smaller micropentactines with straight rays are met. In a 
spicule of this kind the rays measured were 4 n thick at the base, the apical ray 
was 54 n long; the laterals were 34 n long. 
Of amphidiscs several kinds can be distinguished: — A, large ones, with 
medium anchors the teeth of which are smooth, and have straight or outwardly 
curved, diverging ends; B, large, medium-sized, and small ones with slender 
anchors, the teeth of which bear frill-like, fimbriate membranes on their margins 
and have inwardly curved, convergent ends; and C, small ones with broad 
anchors, the teeth of which appear smooth and have end-parts more or less 
parallel to the shaft. 
I measured 202 amphidiscs. The frequency of the various lengths is repre- 
sented in the following exponential graph (Fig. 15). 
