196 
HYALONEMA (HYALONEMA) AGASSIZI. 
average 100 : 93. It is to be noted that in the smaller small micramphidiscs the 
relative breadth of the anchor is, on the whole, in inverse proportion to their size 
(length) . The curvature of the individual teeth is such that the anchors appear 
rather broad above and that the end-parts of the teeth come to lie parallel or 
nearly parallel to the shaft. 
The small micramphidiscs of the other forms appear to be very similar to 
those of form A. Those of form B (Plate 45, figs. 50-52) are 13.5-31.5 /x long, 
most frequently about 20.1 m- The limit between the larger and smaller kinds 
lies, as in form A, at about 29 Those of form C (Plate 45, figs. 54-58) are 
14-30 ju long, most frequently about 18.3 n. The limit between the larger and the 
smaller kind lies here at about 25.5 /x. Those of form D (Plate 45, fig. 62) are 
13-28 m long, most frequently about 20.1 n. The small micramphidiscs of form 
E are 15-34 ju long, most frequently about 22.2 /x. The limit between the larger 
and smaller kind lies at about 24.4 /j. . The small micramphidiscs of form F 
are 15-33 m long, most frequently about 18.3 /i. The limits between the smallest, 
the intermediate, and the largest kind of small micramphidiscs of this form lie 
at about 20.2 n and 25.4 /x- 
To obtain a clearer insight into the range and character of the variation 
of the length of the small micramphidiscs in the four forms of this sponge I 
Frequency 
Fig. 7. — Small micramphidiscs. 
