124 K. MITSUKUEI : STUDIES ON 



between these. 



The color is brown in many shades : some being decidedly 

 dark, while one from Paumotu is so light that it may be described 

 as white speckled with brown. The specimens from the Okaha 

 Eeef (No. 1229) have a decided yellow tinge. The state and 

 differences of preservation have, no doubt, had a great share in pro- 

 ducing the different appearance of different specimens. By far the 

 largest number show on the dorsum two series of dark brown 

 spots 7 — 8 in number, each series corresponding to each of the two 

 dorsal ambulacra. The specimens from the Okaha Reef have no 

 dark spots but only small brown dots scattered all over the body. 

 The Paumotu specimen has a few dark spots and in addition has 

 minute brown scattered dots. In some, the bases of the pedicels 

 appear as small light specks (Nos. 1195, 1229, 1223 and the 

 Paumotu specimen). In some, the ventrum is lighter than the 

 dorsum, while in others, no difference is discoverable between the 

 two surfaces, except for the brown spots already referred to, and 

 where those spots are absent, no coloration distinguishes the two 

 surfaces. In all the specimens, the groups of buttons are visible 

 as minute dots to the naked eye or at least under a hand-lens. 

 In some, shallow grooves are marked on the outside along the 

 five ambulacra. 



In some specimens, pedicels are more numerous on the 

 ventrum than on the dorsum (Nos. 1224, 1225). In others, pedicels 

 seem uniformly scattered all over the body (Nos. 1194, 1195, 1223, 

 1227, 1229 and the Paumotu specimen): In all, the pedicels seem 

 to be more or less in longitudinal rows along the five ambulacra. 

 In some individuals the ventral median ambulacrum has four 

 rows of pedicels, while the two lateral have two rows each. 

 On the dorsum they are more scattered, but still the rows on the 



