150 Bulletin Vanderbilt Marine Museum, Vol. VII 



each other by the width of the truncate inner distal margin of the 

 central mouth shield. There are twelve to fourteen mouth papillae 

 per jaw-angle, each side of which has one squarish, blunt tooth 

 at the jaw-angle, followed by a second, wider, blunt tooth, then 

 two, elongate, conical subacute, strong teeth, with a cluster of 

 about four smaller, but strong, distally widely rounded or blunt 

 teeth at the apex. The teeth are all strong with wide truncate 

 apices predominant. 



The arms are short, averaging from twice to two and a half 

 times the disk diameter, in the four Pearl Harbor specimens, giv- 

 ing the effect of being rather wide, with the arm spines numerous 

 and closely crowded. The under arm plates are wide, with the 

 distal margin widely convex, about one-fifth longer than the nearly 

 straight proximal margin; the side margins are concave. Two 

 tentacles scales are present, of which the inner one is a trifle the 

 larger and longer and more narrowly tapered distally, while the 

 outer scale is widely convex distally. The side arm plates bear 

 five spines each proximally, distally there are sometimes only four 

 spines. These spines are stout, conical, with blunt, rounded tips 

 and increase very slightly in length from the ventral to the fourth 

 or subdorsal spine, the fifth, or dorsal, spine usually being about 

 equal to the fourth spine in length. The first, or ventral, spine is 

 about 2.25 times as long as the greatest width of the related dorsal 

 arm plate, or equal to about the combined length of two dorsal 

 arm plates. 



The dorsal arm plate has the surface entirely covered with 

 pearly granules, skin-embedded. This plate is somewhat fan- 

 shaped, with the proximal margin about one-half as wide as that 

 of the widely convex distal margin, the paired, oblique, lateral 

 margins uniting these two at a depth only a millimeter shorter 

 than the greatest width of the convex outer margin. 



Each of the twenty-one specimens taken in Kaneohe Bay has 

 the distinctive colour pattern of fine radiating golden yellow lines 

 on the dark brownish black disk. This series shows specimens 

 ranging in size from very young forms having a diameter of 6 

 millimeters to large ones, with a disk diameter of 25 millimeters. 

 The ratio of arm length to disk diameter ranges from 1.5, 2, 2.25, 

 to in very young forms, 2.5. 



