ASTEROIOEA OF NORTH PACIFIC AND AUJACKNT WATKUS — FISHER. 141 



Myonotus differs from Benthopeden in having prominont paxillir bearing on 

 the taliiihim a central movable spine and a circle of accessory spinelets, in not 

 having tlie 0(kl interradial marginal [)lates and spines more prominent than the 

 other supero marginals, and in liaving much more numerous and conspicuous 

 marginal spines. 



MYONOTUS INTERMEDIUS (Fisher). 



PI. 24, fig. ,S; pi. 27, fig. 1; pi. 118, figs, la, 1-1/ 



Aeantharchaster intermeditis Fisher, Zool. Anz., vol. 35, March 29, 1910, p. 551. 



Myonottis inteTmedius Fisher, Ann. and Mag. Nat. Hiat., ser. 8, vol. 7, Jan., 1911, p. 92, figs. 2, 4. 



Diagnosis. — Resembling in general appearance a long-rayed lyuidiuster with 

 odd interradial marginals. Characterized by the very spiny marginals (two or 

 three primary superomaiginal spines, and proximally four or five, distally two or 

 three, inferomarginal spines, both sets with accessory spinules); primary abac- 

 tinal plates with a prominent denticulate sj)ine, surrounded by a single series of 

 much smaller spinelets; papular areas slightly two-lobed on ray, and extending 

 to seventh superomarginal (one-seventh length of ray); furrow spines pro.ximally 

 two, long; distally three, shorter; subambulacral spines two, unequal, much 

 longer than furrow spines; mouth plates with five or six marginal spines graduated 

 in length from long iimer tooth to a short outer spinelct; on actinal surface of 

 mouth plates, five rather long spines in an angular series; doreal muscle bands 

 stout. Rays five; R=158mm. ; r=17mm.; R = S.3 r. Breadth of ray at base, 

 21 mm. 



Description. — Abactinal plates stellate on papular area; lobes of primary 

 plates five to eight; secondary plates with two or three lobes or none; beyond 

 papular area plates are roundish or irregular, closely placed. Abactinal surface 

 has much the appearance of that of Luidiaster dau-soni, but the primary spines 

 are rather more numerous. These s])incs have strongly denticulate sides and each 

 is mounted on a low tabulum and surrounded by a single circle of ten to fifteen 

 short, sharp sjjinelets; secondary plates with one to four or five very inconspicuous 

 spinelets. The primary spines are much shorter than in Nearchaster aciculosus 

 (average 4 or .5 mm.). Beyond the middle of ray, spines are lacking and plates 

 are covered with a uniform nap of minute granuliform spinelets, three or four to a 

 plate. Abactinal pedicellariic are very few and small, with four or five spinelets. 

 Papula; distributed all over disk and to seventh su{)eromarginal, or about one-half 

 length of ray; area distally sliglitly two-lobed. 



Marginal ])Iates not| so evidently alternate as in Nearchaster aciculosus, but 

 they are irregular iu this respect. On some ])arts of ray they appear to be nearly 

 opposite, while near by they alternate. Armature similar to that of Nearchaster 

 aciculosus. Superomarginal spines two or three, surrounded by five to eight very 

 slender and shorter accessory spinules. Numerous well-space<l, small, sharji spine- 

 lets are scattered over plate, mostly near the larger sjiines. Inferomarginals with 

 pro.ximally four or five s])ines; farther along ray, two or three. Accessory spinules 

 prominent. There are five odd interradial marginals in both series, scarcely if any 

 larger than adjacent plates although placed on a slightly higher level. Each bears 

 two une(iual or subequal spines, not quite so long as the adjacent superomarginal 



