276 APPENDIX. No. IX. 



remarks at the same time that in none of the Danish examples 

 examined by him do the under arm-plates touch. 



The largest specimen was taken by Capt. Feilden in 

 Franklin Pierce Bay, the diameter of the disk (dried) being 

 10 millims. 



Ophioglypha Stuwitzii (Liitken), Lyman. 



Two specimens were collected by Capt. Feilden in a 

 dredging made in lat. 65° N.,* twenty-six miles from the 

 Greenland coast, depth 30 fms. 



Ophiocten sericeum (Forbes), Ljungman. 



Coll. Feilden: Discovery Bay, 25 fms., hard bottom; 

 Cape Frazer, 80 fms. ; Hayes Point, 35 fms., bottom-tem- 

 perature 29°*5. 



Coll. Hart : Discovery Bay, 15-20 fms., muddy bottom, 

 also at 11 fms. ; Franklin Pierce Bay, 13-15 fms. 



Disk very flat, with margin forming a sharp angle ; 

 covered with imbricating scales and a superficial squamo- 

 granular layer, through which only portions of the radial 

 shields and primary plates are visible. No disk-incisions, 

 the disk forming a little arch over the base of the arms. A 

 row of papillae edges the genital slit, and passes over the arm 

 along the disk-margin continuous with the series from the 

 other side. The first three, or sometimes four, upper arm- 

 plates at the base bear papillae. Side arm plates meet below, 

 but not above. One tentacle-scale. Three arm- spines, 

 arranged along the outer edge of the side arm-plate, the two 

 upper spines being much the largest. 



The main variation which we have noted in the Arctic 

 specimens of this species consists in the greater length of the 

 arm-spines as compared with those of more southern examples. 

 In a specimen 9*2 millims. in disk- diameter the length of 

 the upper arm-spine of the sixth joint was 1*85 millim. (in 

 one case 2*3 millims. !) ; in another, with a diameter of disk 

 of 8*5 millims., the same spine was 1*8 millim. long, three 



