Boone, Echinodermata, Cruises of "Eagle" and " Ara," 1921-28 109 



plates which are bare and which form a rosette in the center with 

 ten radiating arms, five of which are interbrachial and five interradial. 

 The primary plates are rounded. The radial plates are pear-seed 

 shaped with the apices directed inward, quite well separated, resem- 

 bling the larger primary plates. Mouth papillae are six to each angle 

 of the mouth and thin, flat, scale-like, squarish with rounded corners. 

 There are twelve teeth, squarish, short, the middle of the cutting edge 

 thickened; the upper ones somewhat narrower than the lower. The 

 mouth-shields are almost oval, slightly pointed within. The side 

 mouth-shields are large, thick, meeting within. The under arm-plates 

 are wider than long, somewhat irregular, not quite touching, the inner 

 and outer margins nearly straight, the inner a little shorter than the 

 outer, the corners very rounded; the lateral margins concave. The 

 side arm-plates encroach a little below between the under arm-plates 

 and are distinctly separated from each other by smooth skin. There 

 are six stout, flattened arm-spines, rather blunt-tipped, the outer four 

 about equal, the lower two shorter, more conical. On the tip joints 

 of the arm the lowest spines are armed with hooks. The tentacle 

 scale is flat, elongate, stout, rounded. The dorsal arm-plates are 

 widely oval, separated from each other, margined by the ten to twelve 

 unequal, closely crowded supplementary pieces. Toward the tips of 

 the arms the dorsal plates become nearly round. 



References: Stella scolopendraides bellis scolopendrica Linck, De 



Stell. Mar., p. 52, pi. 40, fig. 71, 1733. 

 Asterias aculeata Linne, Syst. Nat., ed. 12, p. 1101, 1767. 

 Asterias aculeatus Retzius, Ast. Gen., p. 240, 1783. 

 Asterias aculeata 0. F. Muller, Zool. Dan., p. 29, pi. XCIX, 1789. 

 Ophiura bellis Johnston, Ann. Mag. Nat. Hist., p. 595, 1835. 

 Ophiocoma bellis Forbes, British Starfishes, p. 53, 1841. 

 Ophiopholis aculeata Gray, Rad. Anim. Brit. Mus., p. 25, 1848. — 



Lutken, Kong. Danske Vidensk. Selsk. Skr. 5th Raekke, Bd. 5, 



p. 60, 1861. — Verrill, Proc. Boston Soc. Nat. Hist., vol. X, p. 



344, 1866 ; Rept. U. S. Fish. Comm. for 1873, p. 718, pi. 35, fig. 



270, issued 1873. — Greig, Ophid. Norweg. North Atlantic Exped. 



Zool., 1876-78, p. 20, 1893.— H. L. Clark, Bull. U. S. Bur. Fish. 



for 1902, p. 559, pi. 5, figs. 24-27, pi. 7, figs. 41-42, 1904 ; Mem. 



Mus. Comp. Zool., vol. XXV, p. 267, 1915. — Mortensen, Handb. 



British Echinoderms, p. 204, fig. 116, 1927. 



