14 K. MITSUKUPtl : STUDIES OX 



long and overhang the moutli, being 1 cm. or more long. In a speci- 

 men 9.7 cm. long, I am able to count about 27 and 31 conical 

 warts respectively in each of the longitudinal series immediately on 

 both sides of the median line. The ventral pedicels are numerous 

 and are arranged in three longitudinal zones, two lateral and one 

 median. In each lateral zone the pedicels stand alternately in two 

 rows. The middle zone has also numerous pedicels. In the 

 middle portion of the body, they seem in all specimens to be in 

 from three to four zigzag rows, which arrangement seems to 

 be kept up in some specimens to both extremities ; but in 

 some others, they are gradually reduced to two rows in the 

 anteiormost and posteriormost parts. In most specimens, the 

 pedicels of the two lateral zones are left protruding, while 

 those of the middle zone are strongly contracted. Moreover, 

 the former seem to be slightly greater both in length and 

 diameter, than the latter. This arrangement is more or less 

 obscured in contracted specimens, and even dorsal conical warts 

 become not very apparent. In the young specimen 4.5 cm. long, 

 the arrangement of ambulacral appendages is very clearly brought 

 out, as there is a great deal of space between their bases. The 

 dorsal papillae are in six distinct rows, although the basal conical 

 warts present are not prominent. In the ventrum, the median 

 zone of pedicels is clearly in two rows, although they show a 

 tendency to be disturbed in this by becoming zigzag, especially 

 in the middle third. 



Excepting the supporting rods, the calcareous deposits are of 

 one fundamental type. They nearly all consist of a triradiate 

 basal part, the arms of which stand 120' apart. The distal 

 ends of the arms are more or less enlarged and perforated. The 

 perforation may be single or there may be several. Sometimes 



