10 S. YOSHIWARA. 



regular transverse row on each plate (in., fig. 9). Actinally, rather 

 irregularly scattered between primary tubercles (in., fig. 10). 



Primary tubercles of ambulacrum : these appear at about the 

 same level as those of the interambulacrum, in a single interrupted row 

 along the median ambulacral suture (am., fig. 9% On actinal side 

 (am., fig. 10) they occur one to each plate but so as to form two regular 

 rows on the inside of poriferous zone. Towards the peristome, these 

 rows become more or less interrupted. — Secondary tubercles as on 

 interambulacral plate, only fewer. 



Spines perforated, of four kinds: 1) poison-spines, which are 

 smooth, pointed and with transverse bands of a brownish color ; found 

 all over the abactinal side, where they may be as long as iGmm., and 

 also on the peripheral half of the actinal side, where they are mostly 

 short and do not exceed 7 mm. in length ; 2) stout, slightly bent, 

 cylindrical spines, truncated at free end and borne on all primary 

 tubercles, consisting of crenulated shaft and of simply striated, short, 

 terminal segment open at end (fig. 12) as long as 22 mm., ',>) shorter- 

 spines, covering the main portion of the actinal side, straight, tapering, 

 cylindrical or slightly flattened, mostly smooth ; 4) short spines on the 

 peristome and adjoining parts, club-shaped, curved, flattened, crenulated, 

 with thick sheath of the soft part. 



Pedicellarite of two kinds : one large and long-headed, the other 

 small, long-stemmed and trifid. 



Branchia with branches that give off numerous, closely set, lobose 

 bran chiefs. 



The most prominent feature by which this species can be distin- 

 guished from all known members of the genus, lies in the peculiar- 

 arrangement of the primary tubercles. 



