A MONOGRAPH OP THE EXISTING CRINOIDS 401 



KEY TO THE SPECIES OT THE GEHU3 COMATULIDES 



a'. Cirri XL, 16-17; division series and proximal portion of arms rugged, with strongly developed 

 synarthrial and articular tubercles (southwestern Japan; 311 and ?731 meters). 



dscameros, p. 401. 



a'. Cirri XXII-XXIV, 12-15; division series and proximal portion of arms without synarthrial or 

 articular tubercles (Lesser Sunda and Kei Islands; 520-984 meters) australis, p. 403. 



COMATULIDES DECAMEROS (A. H. Clark) 



Plate 45, Figures 136, 137 

 [See also vol. 1, part 1, fig. 80 (dorsal view), p. 133; part 2, fig. 694 (disk), p. 341] 



Comanthus decameros A. H. CLARK, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 221 (description; 

 off the Goto Is., 170 fathoms); Zool. Anzeiger, vol. 34, No. 11-12, 1909, p. 366 (listed); Proc. 

 U. S. Nat. Mus., vol. 36, 1909, p. 498 (made type of Cominia). 



Cominia decameros A. H. CLARK, Vidensk. Medd. fra den naturhist. Forening i K0benhavn, 1909, 

 p. 150 (off the Goto Is., 170 fathoms; superficial similarity to Heliomelra); Proc. Biol. Soc. 

 Washington, vol. 25, 1912, p. 21 (compared with Cominia australis); Crinoids of the Indian 

 Ocean, 1912, p. 20 (extends down to 170 fathoms); p. 83 (synonymy; record). 



Comatulides decameros A. H. CLARK, Journ. Washington Acad. Sci., vol. 5, No. 6, 1915, p. 214 

 (southern Japanese species; range and its significance); Unstalked Crinoids of the Siboga 

 Exped., 1918, p. IX (relationship with C. austratis) ; p. 32 (in key; range); p. 33 (com- 

 parison with C. australis). 



IComatulides decameros GISL^N, Nova Acta reg. Soc. sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, 

 p. 31 (Bock's station 37; description). 



Diagnostic features. The cirri are XL, 16-17, and the division series and arm 

 bases are rugged, with strongly developed synarthrial and articular tubercles. 



Description. The centrodorsal is discoidal, bearing numerous marginal cirri in 

 roughly 3 irregular and crowded more or less alternating rows. 



The cirri are XL, 16-17, long, slender, and delicate, 20 mm. in length. The 

 first segment is very short, the second varies from slightly longer than broad to about 

 twice as long as broad, the third-sixth are from two and one-half to three times 

 as long as broad, and the following gradually decrease in length, so that the last two 

 are about as long as broad. The opposing spine is represented by a low tubercle. 

 The terminal claw is about as long as the penultimate segment and is moderately 

 stout and moderately curved. 



The ends of the basal rays are very prominent in the angles of the calyx. 



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

 and widely free laterally. The IBr 2 (axillaries) are broadly pentagonal, about twice 

 as broad as long. 



The 10 arms are 125 mm. in length. The first 7 or 8 brachials are slightly 

 wedge-shaped, and those following become triangular and about as long as broad, 

 and distally wedge-shaped again and longer. In the outer portion of the arms the 

 brachials have projecting and finely spinous distal ends. The arms are rugged and 

 tubercular basally, but are not enlarged or swollen. 



Syzygies occur between brachials 3 + 4, again from between brachials 13 + 14 

 to between brachials 17 + 18 (usually nearer the former), and distally at intervals 

 of from 3 to 5 (usually 3 or 4) muscular articulations. 



PI is 23 mm., P 2 is 20 mm., P 3 is 15 mm., and P 4 is 10 mm. in length. 

 The following pinnules increase gradually in length, reaching 22 mm. distally. The 



