200 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



Figure 88. — Pyura curvigona Tokioka: a, the 26 mm. individual from Palau; b, right half 

 of mantle body, inner side; c, left half of same; d, spinule from inner surface of siphons, 

 highly magnified; e, outline of iridescent bodies, highly magnified; /, ciliated groove; 

 g, tip of ramified branch from posterior part of liver. 



on surface and partly emits bluish-green iridescence, whicli may be 

 observed over nearly all of body surface of smallest specimen. Tliis 

 iridescence caused by spinules distributed in those parts of test and 

 also found on inner surface of distal parts of siphons. Spinules very 

 long, up to 275/i, in length, each provided with a heart-shaped base 

 (fig. 88e) which emits iridescence. Larger spinules striated with about 

 10 fibrous structures, their bases considerably elongated, attaining 

 half of spinule's length. Mantle thick at siphonal area, but thm and 



