PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 619 



p. 542 (faunal affinities); No. 503, p. 725 (color); Geogr. Journ., vol. 32, No. 6, 1908, p. 603 (faunal 

 affinities); Proc. Biol. Soc. Washington, vol. 22, 1909, p. 176 (referred to the Heliometrinae); 

 Internal. Rev. gesamt. Hydrobiol. und Hydrogr., vol. 6, 1914, pp. 6 and following (range); 

 Die Crinoiden der Antarktis, 1915, p. 145 (synonymy; diagnosis; range), p. 182 (range); Journ. 

 Washington Acad. Sci., vol. 7, 1917, No. 5, p. 127 (referred to the Isometrinae) ; No. 16, p. 510 

 (only genus in the subfamily Isometrinae). MORTEXSEN, Vid. Modd. Nat. Foren. K0benhavn, 

 vol. 68, 1917, p. 207 (discussion); Wiss. Ergeb. schwed. Siidpolar-Exped. 1901-1903, vol. 6, 

 Lief. 8, 1918, p. 13 (discussion). A. H. CLARK, Unstalked crinoids of the Siboga-Exped., 1918, 

 p. 239 (only genus in the Isometrinae). MORTENSEN, Studies in the development of crinoids, 

 vol. 16, 1920, p. 31 (discussion). BATHER, Nature, vol. 107, 1921, pp. 132, 133 (review of 

 Mortensen). A. H. CLARK, The Danish Inr/olf-Exped., vol. 4, No. 5, Crinoidea, 1923, p. 42 

 (range). GISLEN, Zool. Bidrag Uppsala, vol. 9, 1924, pp. 56, 94, 100, 101. MORTEXSEN and 

 LIEBERKIXD, Die Tierwelt der Nord- und Ostsee, vol. 12, 1928, p. viii. 108 (care of brood). 

 MORTENSEN, Kongl. Danske Vid. Selsk. Skr., nat. math., ser. 9, vol. 7, No. 1, 1937, p. 63 (com- 

 parison of larvae with those of Lamprometra) . A. H. CLARK, Sci. Rep. Australasian Antarctic 

 Exped., 1911-14, ser. C, vol. 8, pt. 4, 1937, p. 6 (range). JOHN, Proc. Linn. Soc. London, sess. 

 149, pt. 2, 1937, p. 86 (brood pouch, sexual differentiation) ; Discovery Reports, vol. 18, 1938, p. 125 

 (3 new species), p. 127 (only genus in which skeleton is modified by viviparity), p. 130 (4 Antarctic 

 and 2 South American species), pp. 174-175 (lineata, the type species, not a synonym of angusti- 

 pinna), p. 184 (covering plates), pp. 190, 192; Rep. B.A.N.Z. Antarctic Res. Exped. 1929-31, 

 ser. B, vol. 4, pt. 6, 1939, p. 26. CUENOT in Grasse, Traite de zoologie, vol. 11, 1948, p. 55; 

 DAWYDOFF in the same work, pp. 315, 355, 356 (larva). GISLEN, Rep. Swedish Deep Sea 

 Exped., vol. 2, Zool., No. 4, 1951, p. 55. 



Type species. Antedon lineata Carpenter, 1888 (non Pomel, 1887), renamed A. 

 challenged, by A.H.C. in 1907. 



Geographical range. From off the southern tip of Brazil to the Falkland Islands 

 area, the Shag Rocks, the South Shetlands and Graham Land, around the Antarctic 

 continent to the Ross Sea and Enderby and MacRobertson Lands. 



Bathymetrical range. From 79 to 1097 meters. 



Thermal range. From 1.90 C. to +8.30 C. 



Salinity range. From 33.79 to 34.85 parts per thousand. 



Remarks [by A.M.C.]. In the manuscript Mr. Clark had included 1. challenged 

 (lineata) in the synonymy of angustipinna. Since John (1938) showed that the two are 

 distinct, although the holotypes were from the same Challenger station, I have modified 

 this section accordingly. 



No key to the species had been made and I found some difficulty in preparing one, 

 especially since two of the seven species challengeri and angustipinna are known only 

 from single specimens, the liolotype of the latter having an arm length of only about 25 

 mm. It seems to me that challengeri is very close to vivipara (which has also been re- 

 corded from off Uruguay but in less deep water). It appears to differ only in having 

 relatively fewer segments in the first two pinnules at a comparable size. 



A study of the range of variation of the species of Isometra arising from the attempt 

 to construct a key has forced me to erect a new species, Isometra johanni, for the 

 B.A.N.Z.A.R.E. specimens named graminea by Dr. Dilwyn John in 1939, which I am 

 unable to reconcile with his original Discovery specimens of graminea. 



Some idea of the relative proportions and variations with size of certain characters 

 can be obtained from table 15, prepared from a number of specimens in the British 

 Museum collections. Some of the data have also been plotted on a scatter diagram 

 (see Addenda, p. 835) to illustrate the relative proportions of PI and P 2 in the species 

 where more than one specimen is known. 



