94 



PUOF. P. M. DUNCAN ON THE OPHTURTDJ-: 



arms 130 raillim. in length, the upper, swollen, large, flat arm-spine 

 is on every other side arm-plate, and near the end of the arm the 

 upper spine is the longest and largest, but it is neither flat nor 

 swollen. In one of the arms the normal repetition of a large flat 

 spine occurs on every side arm-plate. The granulation of the 

 disk is hemispherical, small, and not crowded ; the largest nodules 

 are on the ends of the radial shields. The granulation is smaller 

 below. The wide generative slits come inwards so as to be 

 bounded orally by the side mouth-shields, and these do not always 

 meet orally. Two or three mouth-papillae merge into a ridge, and 

 the inner mouth-papillae are not readily distinguished from the 

 lower tooth-papillae. The mouth-shields project considerably 

 along the median line into the jaw-angles. The first three lower 

 arm-plates form a groove. The double tentacle-scale is seen near 

 the disk, but not very far out in the arm ; there it is single, large, 

 and flap-like. At the tip of the arm the lower arm-plates are 

 very long. 



In a smaller specimen (diameter of disk 22 millim., length of arm 

 120 millim.) the spines are shorter than in the form just noticed, 

 the lower arm-plates are broadly elliptical in mid-arm, the skin 

 coming well between them. There is no coalescence of the mouth- 

 papillae, and there are three on either side and one below the 

 tooth- papillae. 



The large tentacle-scale in contact with the side mouth-shield 

 and first arm-plate may be counted besides as a mouth-papilla. 



In a small specimen (disk 9 millim. and arm 65 millim.) the 

 granulation of the disk is crowded above and large at the margin. 

 Underneath, the minute scaling, which is obscured by pigment in 

 the large forms, is visible and the granulation does not exteud en 

 masse to the mouth-shields and only a few stray nodules occur 

 thus far inwards. 



The mouth-papillae are either confused with the lower tooth- 

 papillae or are not, or one may be on the jaw-angle external to 

 the tooth-papillae clump. Including the large tentacle-scale, there 

 are four mouth-papillae on either side. The side arm-plates come 

 under the arm and are in contact near the disk, but not further 

 out. The lower arm -plates are rather hatchet-shaped beyond the 

 disk, but they become very long towards the tip. The upper 

 arm-platei are widest withoul and convej there. The spines are 

 miniatures of those of the large forms. Two tentacle-scales near 

 the disk and one further out. 



