PLATE 26. 
1-12. Echinonéus cyclostomus Lreske. 
1-S.— Order in which number of primary tubercles increase on the seventh plate from actinostome, 
including the primordial; from left anterior interambulacrum, bordering on odd anterior ambulacrum, 
is as follows. 
1.— Seventh plate from mouth from a specimen 4.19 mm. long 
2.— Seventh plate from mouth from a specimen 6 mm. long. 
3.— Seventh plate from mouth from a specimen 8 mm. long. 
4.— Seventh plate from mouth from a specimen 10 mm. long. 
5.— Seventh plate from mouth from a specimen 12 mm. long. 
6.— Seventh plate from mouth from a specimen 15 mm. long. 
7.— Seventh plate from mouth from a specimen 17 mm. long. 
8.— Seventh plate from mouth from a specimen 26 mm. long. 
1-8.— From alcoholic specimens. Port Antonio, Jamaica. ~~ 
9.— Part of test showing primary and glassy tubercles, from left anterior interambulacrum, fourth 
plate from actinostome. Diameter of boss 0.35 mm. ; 
10.— Same as previous, from right anterior interambulacrum, midway between ambitus and genital 
plate. Diameter of boss 0.29 mm. 
11.— Half profile of a glassy tubercle, diameter 0.37 mm. 
12.— Same in profile, and section of test. 
9-12.— From an alcoholic specimen measuring 27 mm. long. Makemo Island, Paumotu Islands. 
Figures 1-8, same enlargement. 
