214 
HYALONEMA (HYALONEMA) PLACUNA. 
less equal, or two larger and four more or less rudimentary rays. If this assump- 
tion is correct, and if the energy saved in the building of the smaller rays is 
utilised in increasing the size of the larger, the latter must be hypertrophic to 
a degree in proportion to the degree of reduction of the former as, in fact, 
they are. 
The arnphidiscs. As these spicules are more numerous in form B than in 
form A, I shall commence the description of them with an examination of the 
arnphidiscs of the former. 
The arnphidiscs of form B are 18.5-3b7 ^ long. The frequency of those of 
different length is shown in Figure 9. 
Macramphidiscs 
Micramphidiscs 
w anchors 
d anchors 
inoHcoiflOHOo^fflcow^cBaoooNNffln^iON 
i N®Hrilriodd^N-ilOoi^ 6 <ONC>CON(DN<jiNtDH 
CTHHOJC\](MC\lCOCOCO\l < xt'q , LOtD^NGOCO(jlOrHC^^lON 
OO^NtDCO\tCh^Cq 
a^NCOrH 0 ^^COLO 
COOC\]LONOrO0O 
rH CM CY1 CM CM CO CO CO ^ 
’(DinOiHcoiooHOO^oco^^o^oocxMiMajro^i^ 
lONairHcoincxid^NrMifiai^ddwdooNCDiNaicvicD 
HHHMWCMtNCOCOCO^xfxtLOCDONOOGOOOHW^LO 
oo ^ ^ 
NCOOMLONOCO0 
HHCMCMCMCMCOCOCO 
Fig. 9. — Form B. Arnphidiscs. 
The figure shows that, apart from minor depressions of the frequency-curve, 
the arnphidiscs can, biometrically (according to the frequency of those of different 
lengths), be divided into two main-groups, one comprising arnphidiscs 18.5-48 m 
long, the other arnphidiscs 124-367 tx. These groups dimensionally so very 
different are connected only by three of the 96 arnphidiscs measured, which are 
55, 72, and 100 /x long respectively. The part of the curve pertaining to the small 
arnphidiscs exhibits three not very deep depressions, the part of it pertaining to 
the large arnphidiscs one small and one considerable depression. The latter lies 
between arnphidiscs 187 and 214 m long. 
