256 



ART. 2. — H. MA.TSUMOTO ; 



Nnmerons specimens ; Sagami Sea. Numerous specimens ; 

 Sagami Sea ; 75-100 fathoms. 



Diameter of disk 6 mm. Length of arms 13 mm. Width of 

 arms at base 1.5 mm. 



Disk pentagonal or circular (especially when the animal con- 

 tains many embryos), convex, covered with fifty to sixty plates 

 on the dorsal side, including the radial shields. Central plate 

 pentagonal. Five radiais also pentagonal, directly surrounding the 

 central plate, laterally overlapping each other. In each inter- 

 radial space of the dorsal side, there occm^s a large squarish 



plate, wider than long, and in 

 contact with the radial shields. 

 The latter are irregular in out- 

 line, about as long as wide, one 

 of a pair overlapping the other, 

 instead of being apposed to each 

 other in the radial line. On the 

 ventral side of the disk, the 

 plates are rounded and knob- 

 like, with furrows between ; 

 outer ones larger. Genital papilla? 

 blunt, close-set ; longer outwards 

 and upwards, where they form 

 small arm combs. 



Oral sliields pear-shaped, 

 much longer than wide, wider 

 without than within, with acute 

 inner angle and perfectly rounded outer border. Adorai shields 

 large, meeting within along their whole width. Five oral papiUae 

 on either side, squarish, very short, wide, close- set. A pair of 



Pig. 70. Stegophiurci vivipara. x8. a. From 

 above, h. From below, c. Side view of three 

 arm joints near disk. 



