PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 421 



Carpenter a synonym of this species ; rhomboidea P. H. Carpenter a synonym of magellanica and 

 not of this species as inadvertently stated in the Bull. Mus. Hist. Nat. Paris, 1911, No. 4, p. 258) ; 

 Journ. Washington Acad. Sci., vol. 5, No. 3, 1915, p. 81 (antarctic; range); Die Crinolden 

 der Antarktis, 1915, p. 107 (in key to the antarctic crinoids), p. 122 (characters), p. 168 (a shallow 

 water antarctic form; a species of the Gauss and Victoria quadrants lacking in the Weddell 

 and Ross quadrants), pp. 190-192 (further discussion). GISLN, Ark. Zool., vol. 19, 1928, p. 

 11 (notes; a specimen so labeled in the British Museum is of Florometra magellanica). A. H. 

 CLARK, Sci. Rep. Australasian Antarctic Exped., 1911-1914, ser. C, vol. 8, pt. 4, 1937, p. 7 

 (in key), p. 9 (stations 1 and 3), p. 10 (distribution; color; diagnostic characters). JOHN, Proc. 

 Linn. Soc. London, sess. 149, pt. 2, 1937, p. 85 (Antarctic), p. 86 (not taken by Discovery Inves- 

 tigations); Discovery Reports, vol. 18, 1938, p. 124 (not taken by Discovery Investigations), 

 p. 129 (table of distribution), p. 132 (in key to Antarctic comatulids), p. 152 (Bell's Ross Sea 

 specimens not this species; known distribution only Heard Island and Adelie Land); Rep. B.A. 

 N.Z. Antarctic Res. Exped. 1929-1931, ser. B, vol. 4, pt. 6, 1939, p. 191 (not taken by B.A.N.Z. 

 A.R.E. though collecting in the sector where it has been reported). 



Promachocrinus (Solanometra) anlarctica, A. H. CLARK, Die Crinoiden der Antarktis, 1915, p. 105 

 (collected by the Challenger; history), p. 106 (collected by the Discovery), p. 135 (synonymy; 

 range; r<5sum6 of previous records). 



Antedon (Solanometra) anlarctica GISLN, Zool. Bidrag Uppsala, vol. 9, 1924, p. 287. 



Promachocrinus antarctica EKMAN, Tiergeographie des Meeres, 1935, p. 319. 



Diagnostic features. This species is most easily distinguished from its relatives 

 by the short cirri composed of rarely more than 40, and usually not more than 30 

 segments of which the longest are rarely, even in immature specimens, more than 

 twice as long as broad, most of them, in large cirri, being as broad as long. The cirrus 

 segments have rather flaring ends particularly dorsally, which give the cirri a char- 

 acteristic knobby appearance. The axillaries are very broad, broader than long. 

 The brachials beyond the oblong proximal ones are short, twice as broad as the greater 

 length. P 3 is more like P 4 than it is like P 2 , and the segments of the outer pinnules 

 are strikingly short. 



Description. The ceutrodorsal is hemispherical or low rounded conical, thickly 

 covered with cirrus sockets which are arranged in more or less regular closely crowded 

 alternating rows. 



The cirri are LXXX or more, 25-35 (usually 25-30), the longest reaching 35 

 mm. in length, but the majority being between 25 and 30 mm. long; the apical cirri 

 measure about 11 mm. and consist of about 17 segments. In the longest cirri the 

 first two segments are about twice as broad as long, the third is somewhat longer, 

 the fourth is longer than broad, and the fifth to ninth are nearly twice as long as broad ; 

 from this point the length of the segments gradually decreases so that the outermost 

 are only about a third again as long as broad. On the thirteenth the median portion 

 of the dorsal edge begins to project somewhat, two or three segments beyond forming 

 a moderately developed dorsal spine; this decreases in size on the terminal three or 

 four segments. The opposing spine is very small. The terminal claw is about as 

 long as the penultimate segment, moderately stout and moderately curved. The 

 majority of the cirri are somewhat shorter with somewhat fewer segments, all, or 

 nearly all, of which are about as long as broad, and the dorsal spines are compara- 

 tively small. In the very short apical cirri the first two segments are short, and the 

 remainder are about as long as broad; dorsal spines are developed from the third or 

 fourth onward. 



The ends of the basal rays are sometimes visible in the angles of the calyx. 



