62 ART. 2 -S. YOSHIWARA: 



my specimens of it closely resemble E. j)laee)Ua Duncan and Sladen* 

 from the Miocene of India. lîiit the latter species has broader lunules 

 running- in a line through the apical system to the tip of the petals; the 

 petals are open and have less numerous ambulacral pores; and the tip 

 of the petal is very distant from the lunule. Our species of Echino- 

 discus, as well as of Astrid i/jieus were erroneously described by Prof. 

 Lebour as E. hioculatua Ag. and E. bisperforatus Leske.f The largest 

 specimen of Echinodisciis in my cc^llection has a diameter of 140mm. 

 I propose for it the new specific name E. formosus with the following 

 diagnose. 



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

 widest posteriorly, not so strongly truncated as E. hiocidatus Ag. 

 Apical system nearly central, madreporite central, polygonal; four 

 genital pores exsisting in the basal plates. Petals nearly closed; 

 anterior longest. The length, breadth, and number of the pores 

 in each petal in a specimen of about 100 mm. diameter are as 

 follows: 



Lengtli of Widtli of Number Width of 



petal. petal. of pores, poriferous zone. 



mm. mm. nmi. 



Odd ambulacnuu. 25. 11.5 75 4 



Anterior paired ambulacra. 22.5 11.5 67 4 



Posterior paired ambulacra. 22.5 11.5 67 4 



Lunules two, one in each posterior ambulacral space; large and 



elliptical; 13.5 mm. in length and 9 mm. in width in the same 



specimen; these becoming more elongated in the older specimens: 



larger axis of lunule making about 30° with the median line of 



the ambulacrum. Distance from the tip of petal to the lunule 



only 5 mm. Peristome central, very small; groove single near 



peristome, and soon bifurcating. 



* M. Duncan and W.P. Sladen, The fossil Echinoidea from the Gâj or miocène Series 

 —Mem. Gcol. Survey. India, Ser. XIV , Vol. I. 3., Fas. V. 1885. 



t G.Ä.. Labour, Note on some Fossils from North Formosa. &c. — Trans. North Eng. Inst, 

 of Mining and Mechanical Engineers. Vol. XXXIV., Part. I.. 1885. 



