PLATE 18. 
1-11. Echinonéus cyclostomus LESsKE. 
Valves of tridentate pedicellariae. 
1.— Stalk and head, 0.95 mm. long. ) 
2.— Valve A, 0.51 mm. interior view. } 
3.— Valve B, 0.50 mm. interior view. | 
4.— Valve B, 0.50 mm. interior view, profile. | 
5.— Valve C, 0.47 mm. interior view. 
6.— Valve C, 0.47 mm. exterior view. J 
1-6.— Are from right anterior interambulacrum, midway between the actinal system and the 
ambitus. Dry specimen, with spines measuring 34 mm. long. Lord Howe Island. 
Of a single pedicellaria. 
7.— Valve B, 0.47 mm. interior view, near the actinostome in odd posterior interambulacrum. 
8.— Valve B, 0.47 mm. exterior view near the actinostome in odd anterior ambulacrum. 
9.— Valve B, 0.45 mm. exterior view midway between actinal system and the ambitus, in right anterior 
interambulacrum. 
7-9.— Alcoholic specimen with spines measuring 15 mm. long. Makemo Island, Paumotu Islands. 
10.— Valve C, 0.22 mm. exterior view. 
11.— Valve C, 0.22 mm. interior view towards ambitus, actinal side, in left posterior interambulacrum. 
Test measuring 34 mm. long. Lord Howe Island. 
The measurement refers to height of valves natural size. 
All of the same enlargement with exception of Figure 1, which is on a smaller scale. 
