ACTINOPODOUS HOLOTHURIOIDEA. 55 



individuals these rings formed white patches, Avhich were most 

 conspicuous along the sides and around the cloaca, sometimes 

 turning into white the prominent color of these regions or even of 

 the whole dorsum. In other individuals, the rings were confined 

 to a few papillae along the sides or around the cloaca. 



Tentacles 25 — 27 (two individuals from Ogasawara Is. had 

 25 and two others 27). Another smaller individual from the same 

 locality had only 20. Whether this was due to some tentacles 

 having been lost, or to the young individual not having a full 

 complement, could not be ascertained. 



Calcareous deposits in the dorsal perisome : (i) numerous 

 slender elongate rods with short, mostly simple, occasionally 

 slightly branclied processes along their sides, nnd with a tendency 

 to divide dichotomously at tlie ends (textfig. 11 r/). Length 0.04 

 — 0.13 mm., breadtli 0.004 — 0.007 mm. (ii) Incomplete rosettes, 

 0.034 — 0.02 mm. across {h). \n the ventral perisome : (i) Elongate 

 rods, in general shorter but thicker than those in the dorsal peri- 

 some. In some the margin is smooth ( /'), in others it is beset 

 with fine close-set processes, making it serrate (Ji) ; in still 

 others, there are along the margin well marked |)rocesses, some of 

 which may even be branched (7). The ends of the rods are almost 

 always more or less rough, and sometimes l)ifid. The two eiids 

 are very often different. There avo all stages of gradation 

 between these various forms. Size varying between 0,12 x 

 0.018 mm. and 0.044 x 0.012 mm. (ii) Oval grains, sometimes 

 regularly oval (c), sometimes more oi- less irregular or biscuit- 

 shaped, being pinched in the middle (r/) ; sometimes aggre- 

 gations of small lobes, approaching the rosettes (r). The longest 

 oval grains and shortest rods can not be distinguished. Length 

 and breadth 0.04 x 0.02—0.02 x 0.014 mm. (iii) l^iosettes {a), much 



