94 



I. niMA AND S. IKEDA. 



conspicuous muscular threads, running from the nuchal band to the 

 bases of the first arm-pair. 



The jaws were not examined by us by cutting them out of the 

 buccal mass. 



In the umbrella the arms are now traceable, on both its internal 

 and external surfaces, as ridge-like prominences owing to the shrinking 

 up of the enveloping gelatinous tissue. By the same cause the interpodal 

 edges of the webs have become much thinner and more deeply indented 

 than was the case in the fresh state. The indentation is deepest between 

 the ventral (4th) arm-pair, extending fully half- way up the length of 

 these arms in a moderately outspread state of the web concerned. In 

 the dorsal median web the deepest point of the indentation lies about 

 one-third the arm-length away from the arm-tip. As regards the 

 remaining paired webs, there are indications of their having unequally 

 contracted on the two sides of the umbrella. "We think we may say 

 that they are all equal to the dorsal median web as well as to one 

 another, both in extent and in the manner the ends of the free edge of 

 each insert themselves to the enclosing arms. It is difficult to deter- 

 mine for what fraction of their length the arms are free at the distal 

 end ; we may however approximately estimate it at without going 

 much wide of the mark. Through the skin and especially when seen on 

 the inner surface, the webs show numerous, thin, simple or branched 

 muscular bundles, which run between the oppositely standing sides of 

 every two adjoining arms (Woodcut 1). 



The arms have unequally contracted in length (86 — 96 mm.). It 

 may however be safely said that they are all subequal or nearly equal. 

 They are about twice as long as the head and body taken together. 

 Being somewhat laterally compressed, the thickest part may measure up 

 to 9 mm. across in the lateral view and 6 — 8 mm. when seen from either 

 outside or inside. At base they are somewhat narrower, and in the 

 distal one-third of their length they again show a gradual tapering 

 towards the slender, pointed tip. The cirri are not present. Nor is 



