fossil echinoids of japan. 15 



Localities : — 



Hatto near Kelung, Formosa (Miocene) (coll. S. Tokunaga) ; 

 Iriomote-jiraa, Loochoo Is. (Miocene) (coll. S. Tokunaga). 



ASTRICLYPEUS INTEGER Yosh. 

 PI. I. Figs. 3 and 4. PI. II. Figs. 3 and 4. 



Synonym : Astriclypeus integris Yosh. 

 Literature consulted : — 



S. Yoshiwara, On some new Fossil Echinoids of Japan. — 



Journ. Geol. Soc, Tokyo, Vol. VI., No. 65, 1899. 

 S. Yoshiwara, Geologic Structure of Biukiu Curve etc. — 



Journ. Coll. Sc. Imp. Univ. Tokyo, Vol. XVI. Part 



I., 1901, p, 61. 



Length Greatest width Greatest width of Greatest width Distance of lunule from 

 Diam. of petal. of petal. porif. zone. of interp. zone, the extremity of petal. 



110 mm. 23 mm. 12 mm. 4 mm. 4 mm. 15 mm. 



Test thick, with a circular or elliptical outline, regularly 

 conical, sloping uniformly from vertex to the ambitus. 



Apical system similar in form and structure to Astriclypeus 

 manni Verill. 



All the petals nearly equal in length and breadth : poriferous 

 zone broad, broadest near the extremity of petals which are nearly 

 closed at the extremity ; number of pores 37 in a specimen measur- 

 ing 110 mm. in diameter; thus differing from living Astriclypeus. 



Each of five lunules oval, very wide (14 mm.: 9 mm.), 

 constituting the characteristic feature of this species. 



Lower surface flat, teeth similar to those in the allied species. 

 Actinal groove and tubercles not preserved. 



