A MONOGRAPH OF THE EXISTING CRINOIDS 565 



C. pinguis and C. solaster); Zool. Bidrag Wn Uppsala, vol. 9, 1924, p. 41 (details of arms); 

 p. 42 (angles of brachials); p. 44 (reversion); pp. 46, 51 (obliquity of joint faces); p. 53 (axillary- 

 angle) ; p. 77 (syzygies) ; p. 88 (articulations) ; fig. 66, p. 75 (syzygial face) ; fig. 96, p. 87 (syn- 

 arthrial face). 



Aclinomelra trichoptera Hartlaub, Mem. Mus. Comp. Zool., vol. 27, No. 4, 1912, p. 477 (Yeddo 

 Bay; notes). 



Aclinometra japonica var. morsei Hartlaub, Mem. Mils. Comp. Zool., vol. 27, No. 4, 1912, p. 477 

 (Yeddo Bay; notes). 



Aciinometra spinipinna Hartladb, Mem. Mus. Comp. Zool., vol. 27, No. 4, 1912, p. 478 (descrip- 

 tion; 71oc.); pi. 15, fig. 12. 



Comanthus (Bennetlia) japonica A. H. Clark, Journ. Washington Acad. Sci., vol. 5, No. 6, 1915, 

 p. 214 (southern Japanese species; range and its significance). 



Comanlhus solaster Gislen, Nova Acta reg. Soc. sci. Upsaliensis, ser. 4, vol 5, No. 6, 1922, pp. 

 43-46 (Bock's stations 20, 28, 38; notes); figs. 33, 34, p. 44. 



Comanlhus solaster forma muUicirra Gisl6n, Nova Acta reg. Soc. sci. Upsaliensis, ser. 4, vol. 5, 

 No. 6, 1922, p. 46 (diagnosis; Bock's stations 20, 28, 38A). 



Comanthus japonicus Gislen, Vidensk. Medd. fra Dansk naturh. Foren., vol. 83, 1927, p. 13 

 (Mortensen's stations 1, 27; notes). 



Diagnostic features. — In large specimens the centrodorsal is large and more or 

 less hemispherical, with the dorsal pole concave. The cirri are numerous, large and 

 stout, with 19-36 (usually about 30) segments of which the terminal 10 or 12 are from 

 one-third again to twice as broad as long and bear dorsally a subterminal tubercle 

 or blunt spine. The arms are 13-50 (usually 30-40) in number, from 80 to 180 mm. 

 (usually from 100 to 150 mm.) in length. The division series are narrow and very 

 strongly convex dorsally, and are widely separated laterally. 



Apparentlj' fully developed specimens are frequent in which the cirri have 

 about 20 segments and the arms are 20-25 in number. 



Excepting for its narrow and widely separated division series this species in all 

 respects very closely resembles C. pinguis. 



Description. — The centrodorsal is discoidal, moderately thick, with the polar 

 area broad, flat, or slightly concave, from 4 to 6 mm. in diameter. The cirrus sockets 

 are arranged in 2 closely crowded alternating, but more or less irregular, marginal rows. 



The cirri are XX-L (usually XX-XXX), 19-23 (usually 20), from 17 to 23 mm. 

 long. They are moderately stout, well rounded in cross section in the pro.ximal 

 half but laterally compressed in the distal half and therefore appearing in lateral 

 view broader distally than pro.ximally. The first segment is short, the second is 

 longer, the third is about as long as broad, and the fifth-seventh are nearly or quite 

 twice as long as broad. The segments following decrease in length so that the 

 last 8 or 10 are from one-third to one-half again as broad as long. The seventh or 

 eighth is usually a well-marked transition segment. The transition and following 

 segments have the dorsal portion of the distal edge somewhat thickened, this soon 

 becoming a small subterminal tubercle. The opposing spine is a low but usually 

 sharp tubercle with the apex varying from median to terminal, though commonly 

 nearer the former. The terminal claw is considerably longer than the penultimate 

 segment, and is slender and relatively slightly curved. 



The radials are concealed by the centrodorsal. The IBri are oblong, short, 

 about four times as broad as long, and entirely free laterally. The IBra (a.xillaries) 

 are triangular, twice as broad as long, with the anterior angle rather sharp. The 



