OPHTACTIS. 123 
shields moderate; covering-plates of disk stout, numerous, im- 
bricating. Arms stout, never long, with strong, solid, smooth 
spines. 
Key to the Species. 
Two mouth-papill.......... 1. O. abyssicola. 
One mouth-papilla .......... 2. O. balli. 
1. Ophiactis abyssicola. 
Amphiura abyssicola, Sars, Norg. Ech. (1861) p. 18, pl. it. figs. 7-12. 
Ophioenida abyssicola, Lyman, Lil. Cat. Mus. C. Zi. (1865) p. 12. 
Ophiactis abyssicola, Ljungman, ifv. Vet.- Akad, Forh. 1866 (1867), 
p. 324; Lyman, Chall. Rep. Oph. (1882) p. 122; itd. Proc. R. Soe. 
Ed. xi. (1882) p. 707 ; Hoyle, op. cit. xii. (1884) pp. 710,715, 718 ; 
id. Proc. R. Phys. Soc, Ed. viii. (1884) p. 145. 
A rather small species, with stout scales and rather stronger arms. 
Disk-scales very unequal in size, thickened; many of them carry 
stout spines. Radial shields rather large, separated each from 
its fellow by three or four small plates ; they have an irregularly 
straight inner and a convex outer edge. ‘Two mouth-papille. 
Three or four stoutish arm-spines, the uppermost the longest and as 
long as the upper arm-plates; the side-plates encroach consider- 
ably on the upper and lower plates, both of which are much wider 
distally than proximally; the upper arm-plate is very narrow 
proximally. 
Colour, in spirit, white: ‘“ laete carneus seu aurantiacus, in medio 
dorso subfusco-carneus, spinis pallidioribus ” (Sars). 
p= 45-2°5; R=22-30. 
Distribution. Coasts of Norway. 64-767 fms. 
a, b, Faeroe Channel, 542 fms. ‘ Porcupine’ Exp. (St. 47 a). 
c-f. Faeroe Channel, 440 fms. ‘Porcupine’ Exp. (St. 51). 
g-p. Faeroe Channel, 384 fms. * Porcupine’ Exp. (St. 52). 
g. Faeroe Channel, 345 fms. ‘ Porcupine’ Exp. (St. 65). 
r-w. Faeroe Channel, 458 fms. ‘ Porcupine’ Exp. (St. 90). 
wv. East of Shetland, 203 fms.* ‘ Porcupine’ Exp. (St. 74). 
y, 2, a’'-c’. No loc. Wyyvy. Thomson Coll. 
2. Ophiactis balli. 
Ophiocoma ballii, Thompson, Ann. § Mag. v. (1840) p. 99; Forbes, 
Brit. Starf. (1840) p. 85; Thompson, Nat. Hist. Irel. (1856) 
. 437. 
Oiptiicearis goodsiri, Forbes, t. c. p. 57. 
Ophiolepis ballii, M. 7'r. Syst. Ast. (1842) p. 97. 
Ophiolepis goodsiri, wd. ibid. 
Ophiopholis ballii, Gray, Cat. Brit. Rad. (1848) p. 25. 
* Mr. Lyman, who named these specimens, notes that they have few or no 
disk-spines, and have thick scales, 
