114 THE VOYAGE OF H.M.S. CHALLENGER. 



Table of Species of Oiihiactis — continued. 



Disk scales thick and swollen : upper arm plates -ivide, transverse oval, not j 



swollen. Side mouth shields making a connected ring. Four or five ,- Ophiadis simplex. 

 stout hut not swollen arm spines. Small disk spines, . . . ' 



Differs from Ophiadis simplex in wanting disk spines ; in radial shields scarcely | 



to he distinguished from scales (which are less imbricated than in simplex) r Ophiadis arenosa. 

 and Ln more oval upper arm plates, . . . . ■ ' 



Disk scaling coarse, and with few or no spines. Three or foui' stout, blunt, \ 



tapering arm spines. Two or three mouth papLHae on each side. Teeth \ Ophiadis cuspidata. 



lobed, . . . . . . . . . ) 



Disk without spines, and covered with thick, rounded scales, whereof the ) ^ , . ,. , , 

 '^ ' \ Ophiadis peduralc. 



largest are near the radial shields. Two small tentacle scales, . . j 



Disk scales coarse, and set with numerous short spines. Eadial shields short j 



and triangular. Four stout, cylindrical, tapering arm spines. One mouth ■ Ophiadis nama. 

 papilla on each side. Five arms, . . . . . . ,' 



Mouth sliields very wide and short. Always one mouth papilla on each side, - 

 four to five stout smooth long arm spines, usually blunt and tapering, but 

 sometimes the upper ones much swollen; middle ones longest. Disk scales }• Opliiadis kroyeri. 

 coarse above and bolow with variable number of spines. Eadial shields 

 larger than in the type Ophiadis halli, .... 



J 



Large (disk 11-12 mm.) nearly black. Four arm spines; upper one longest. . 



Eadial shields shagreened, small, and rudely diverging. Under arm plates I g^^j^.^^^-^ nigrescens. 



curved without and within ; re-enteringly curved on sides. Upper arm I 



plates truncated fan shape, ...... . 



Five short, smooth, tapering arm spines. Disk scales smooth and rather fine. \ 



Upper arm plates rounded fan shape, not swollen. One mouth papiUa on ,- Opliiadis maculosa. 

 each side, . . . . . • ■ • ' 



Disk finely scaled, and set with short, minute spines. Eadial shields small 



and pear-seed shaped. Four moderately stout tapering arm spines, the t'-l'-f 



uppermost longest. Two or three minute mouth papilte on each side. 

 Seven arms, . . . . . . • • -' 



Disk scales coarse and thick, with large radial shields ; no spines except a few \ 



near the margin. Four rather long and slender arm spines, the upper one ,■ Ophiadis poa. 

 longest. Two mouth papillae on each side, . . . . ' 



Disk scales larger in centre, where primary plates may be distinguished in a - 

 rosette; no spines, or only an occasional minute one on the margin. 

 Three or four rather long and tapering arm spines Two mouth papillre 

 on each side. 



Four long, rather slender arm spines. Many strong disk spines. Disk scales \ 



tlrick and somewhat irregular. Two mouth papilkc on each side. \ Ophiadis abyssicola. 

 Teeth lobed, . . . . . . • • / 



Structure more delicate. One mouth papiUa. Eadial shields very small. \ 



Disk scales small, fine and regular. Four arm spines about as large as in ,■ Ophiadis i-arnea. 

 Ophiadis aqxrula. Upper arm plates clean, transverse oval, . . / 



Ophiadis canotia. 



