14 AßT. 12. S. TOKUNACÎA : ON THE 



Gaspé; Mingan Is.; Straits' Bell Is.; Gilky Harbour, Meine; N. 

 Australia ; Red Sea ; India. 



ECHINODISCUS FORMOSUS Yosh. 



PL I. Fig. 1 and 2. PL II. Fig. 2. 



Literature consulted : — 



S. Yoshiwara, On the Geologic Structure of Kiukiu Is. etc. 

 — Journ. Coll. Sc. Imp. Univ., Tokyo, Vol. XVL, 

 Part I., 1901, p. G2. 



Length odd Width No. of pores Length ant. Width ant. 



Diam. petal. odd petal. in odd petal. paired petal. paired petal. 



100 mm. 25 mm. 11.5 mm. 75. 22.5 mm. 115 mm. 



No. of pores in Length post. Width post. Width of Distance from the extremity 

 ant. paired petal, paired petal. paired petal, poriferous zone. of petal to lunule. 



(>7. 22.5 nun. 6.7 mm. 4 mm. 5 mm. 



Test thin, very slightly raised dorsally ; broadly ovoid, widest 

 posteriorly, not so strongly truncated as in Echinodiscus bioculatus 

 Ag.; the largest specimen having a diameter of 140 mm. 



Apical system nearly central ; madreporite central, polygonal; 

 four genital pores existing in the basal plates. 



Petals nearly closed, the anterior being the longest. 



Lunules two, one in each posterior ambulacral space, large 

 and elliptical; 13.5mm. in length and 9mm. in width in a 

 specimen 100 mm. in diameter ; the longer axis of the lunule 

 making an angle of about 30° with the median line of the 

 ambulacrum ; distance from the extremity of the petal to the 

 lunule only 5 mm. 



Peristome central, very small ; groove single near peristome, 

 and soon bifurcating. 



