458 



PEOF. P. M. DUNCAN ON SOME 



"but only to the sixth or seventh lower arm-plate; and their 

 lamellar nature is remarkable. The mouth-plates are more 

 distinct. 



Several still smaller specimens show the general arrangement 

 of the disk-scales, have a spine here and there on the second 

 upper arm-plate, and the side arm-plates unite above between the 

 second and third upper arm-plates. Beneath, the tentacle-scale 

 ceases on the fifth lower arm-plate, and the side arm-plates join 

 between the third and fourth or fourth and fifth lower arm-plates. 

 The jaws are thicker and the mouth-papillae are less developed 

 than in the larger forms. Therfe is a tendency of the tentacular 

 scales to form ridges, and of the spines to split. 



Locality. Korean Straits, 23 fathoms. Collected by Capt. 

 St. John, E.N. 



In the British Museum. 



OpnioGLTPnA Sladeni, sp. nov. Plate IX. figs. 9, 10, & 11. 



The disk is pentagonal, thick, much notched above the arms, 

 which are short, straight, and tapering, and not quite twice as 

 long as the diameter of the body. 



The upper surface of the disk is covered with numerous rather 

 tumid scales of all sizes, disposed without much regularity, some- 

 times overlapping and usually in mosaic. A large central scale is 

 circular in outline, and has a slight boss on it, and four large 

 scales of the rosette with a small one surround it, being sepa- 

 rated by smaller scales. Each of the outer large scales has 

 three smaller ones on its distal edge, the central scale of the three 

 being fixed in between the radial shields. 



The radial shields are longer than broad, have their inner 

 and outer ends nearly equal, and their inner sides united for a 

 short space, and the outer sides are curved ; separated slightly 

 orally by one scale, they are widely apart without and are placed 

 obliquely. The shields do not reach the margin of the disk, and 

 each terminates without in a long radial scale, curved without 

 and furnished with fourteen close, distinct, short, slender spines. 

 The iuterbrachial spaces are straight and they are boldly sealed. 

 The mouth-shields are large, and reach without, close to the ver- 

 tical margin of the iuterbrachial spaces ; they are longer than 

 broad, with a very pointed angle within and a broad curve with- 

 out, the sides sloping from the broad base to the sharp angle. 



The side mouth-shields are small, short, narrow, and united at 



