278 
Holothuria atra 
1894, thinks that the variety amboinensis must be given up because of colour 
intermediates from deep black to clear yellow at the basis from which the 
ambulacral appendages arise. 
TABLE XXIX. 
C. Tentacles and Ampullae. 
a. Number of Tentacles. 
Adult 
Young 
Number of Specimens 
Mean 
Standard l^eviation 
Coefficient of Variation . . . 
Range of Variation 
12 
19-583+ -169 
-868+ -120 
4-430 + -610 
18—21 
8 
19-125+ -278 
1-166+ -196 
6-096+1-028 
17—20 
The 20 tentacles normally found as the mode in H. atra are distributed 
according to the scheme of symmetry given for H. floridana (cf. Fig. A, PI. V.). 
Variation in the Number of Tentacles and the Relation of those Present to the 
Normal Symmetry. 
TABLE XXX. 
Variations ivith less than 20 Tentacles. 
Distribution in accord with the scheme of symmetry given in Fig. A. Absence 
of tentacle in particular radius indicated by 0. 
Age 
Serial 
Number 
Eight Dorsal 
Left Dorsal 
Bight Ventral 
Left Ventral 
Mid- Ventral 
Total 
Number 
dl 
d2 
vl 
dl 
d2 
v2 
vl 
dl 
d2 
vl 
dl 
d2 
v2 
vl 
11 
12 
/•2 
rl 
Adult 
151 
158 
159 
160 
0 
0 
0 
0 
0 
0 
19 
19 
18 
18 
Young 
165 
166 
168 
0 
0 
0 
0 
0 
0 
0 
18 
18 
17 
Among the 8 variates there is the same decided tendency to reduction in the 
number of tentacles as shown in H. floridana, since 7 (87-5 7^) have less than the 
normal number of 20. Only 1, an adult, 161, with 21 tentacles has more than 
the norm. The extra tentacle is d3, left dorsal radius, and all 5 tentacles of the 
dorsal inter-radius are in asymmetry, to the left of the mesentery. In 151, 158 
and 160 the mesentery is attached at the junction of the dor.sal inter-radiale with 
the right dorsal radiale ; in 161, far over on the right dorsal radiale. 
