A MONOGRAPH OF THE EXISTING CRINOIDS 269 



A fourth has the cirri IX, 12-13. 



The remaining 4 specimens are similar to these. 



Locality. Erg Tor, Gulf of Suez; Dr. Robert Hartmeyer [A. H. Clark, 1911, 

 1912, 1918; Hartmeyer, 1916] (8, and pentacrinoids, U.S.N.M., 34946; Berl. M.). 

 PI. 28, figs. 78, 79; pi. 29, figs. 80-82. 



History. The original specimens of this species I at first (1911) considered as 

 immature individuals, possibly of Comathus parvicirra; but in 1912 I described them 

 as representing a new species of Comissia. 



The pentacrinoids found with them were mentioned in volume 1, part 2, page 514, 

 but not described. 



COMISSIA IGNOTA A. H. Clark 



Aclinometra, sp. nov., BELL, Report Zool. Coll. H. M. S. Alert, 1884, p. 510 (Marie Louise I. and 

 Isle des Neufs). A. H. CLARK, Proc. U. S. Nat. Mus., vol. 40, 1911, p. 3 (recorded by Bell 

 from the Amirante Is.); Smiths. Miscell. Coll., vol. 61, No. 15, 1913, p. 79 (of Bell, 

 1884 = C. ignota). 



Actinometra pectinata (B. M., MS.) A. H. CLARK, Proc. U. S. Nat. Mus., vol. 40, 1911, p. 17; 

 Smiths. Miscell. Coll., vol. 61, No. 15, 1913, p. 7. 



Comanthus (Validia) parvicirra A. H. CLARK, Proc. U. S. Nat. Mus., vol. 40, 1911, p. 19 (Seychelles); 

 vol. 43, 1912, p. 385 (specimens from the Seychelles identified as Comissia ignota). 



Comissia ignota A. H. CLARK, Proc. U. S. Nat. Mus., vol. 40, 1911, p. 8 (southeast Africa); p. 17 

 (synonymy; description; localities); Ann. and Mag. Nat. Hist., ser. 8, vol. 7, 1911, p. 645 

 (listed, with habitat); Proc. U. S. Nat. Mus., vol. 43, 1912, p. 385 (identification of the speci- 

 mens from the Seychelles); p. 386 (Seychelles); Crinoids of the Indian Ocean, 1912, p. 78 

 (synonymy; locality); Smiths. Miscell. Coll., vol. 61, No. 15, 1913, p. 7 (published reference to 

 specimens in the British Museum; localities; 6-rayed specimen); Unstalked Crinoids of the 

 Siboga Exped., 1918, p. 20 (in key; range). GISL^N, Nova Acta reg. Soc. sci. Upsaliensis, ser. 4, 

 vol. 5, No. 6, 1922, p. 7 (a variety found at the Bonin Is.). 



Diagnostic features. The cirri are XII-XV, usually 10-11, from 4 to 5 mm. 

 long; the longest cirrus segment is about three times as long as the median width. 

 The arms are slender, from 30 to 35 mm. long, and the brachials have moderately 

 produced and spinous distal edges. 



Description. The centrodorsal is discoidal, with a flat dorsal pole from 1.5 to 

 2 mm. in diameter. 



The cirri are XII-XV, 9-11 (usually 10-11), from 4 to 5 mm. long. The first 

 segment is short, the second is not quite so long as broad, the third is longer, and the 

 fourth is the longest, about three times as long as the median width. The sixth and 

 following are about as long as broad. The third and fourth are strongly constricted 

 centrally. The fifth and following each bear a minute sharp subterminal tubercle. 

 The shorter distal segments are somewhat compressed laterally, and hence appear 

 comparatively broad in lateral view. The opposing spine is slight and inconspicuous. 



The radials are concealed by the centrodorsal. ThoIBr! are well separated, the 

 interradial angle of separation being about 90. 



The 10 arms are from 30 to 35 mm. in length, and in general resemble those of 

 Leptone master venustus, though they are proportionately slightly stouter. The gonads 

 are developed on the pinnules. 



Abnormal specimen.- One of the individuals collected by H. M. S. Alert at Marie 

 Louise Island is 6-rayed. 



