14 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



B.A.N.Z.A.R.E. station 107; off MacRobertson Land (lat. 6645' S., long. 6203' 

 E.); 219 meters; February 16, 1931 [John, 1939] (11, B.M., 36, Australian Mus.). 



Geographical range. Confined to the immediate vicinity of the Antarctic conti- 

 nent and adjacent islands. 



Bathymetrical range. From 80 to 640 (?731) meters. 



Thermal range. From 0.42 to 1.84 C. 



History. This species was first described by Dr. Th. Mortenseu in 1917 from a 

 series of 15 specimens brought home by the Swedish South Polar Expedition of 1901-03. 

 In the following year he described it in great detail and suggested for it the new family 

 Notocrinidae. In 1920 he gave a detailed account of the early stages. 



Dr. Torsten Gislen in 1924 described and figured a number of structural details 

 from some of the original specimens. 



In 1929 Dr. James A. Grieg recorded and gave notes on a specimen from the South 

 Shetland Islands, and in the same year the author recorded another from Terra Nova 

 station 341. 



In June, 1937, Dr. D. Dilwyn John, in a paper on Antarctic comatulids based 

 primarily on the Discovery collections, discussed this species and described briefly its 

 sexual peculiarities and early stages. In his memoir on the crinoids of the Australasian 

 Antarctic Expedition 1911-14, published on September 27 of the same year, the author 

 recorded it from Aurora stations 1 and 3. 



In 1938, the full Discovery report on the Crinoidea was published, in which Dr. 

 John gave additional information on the characters of the species based on the abundant 

 adult material from the South Shetlands and Ross Sea as well as detailed descriptions of 

 the pentacrinoid larvae of this species. 



The following year, the same author, in reporting on the Crinoidea of the 

 B.A.N.Z.A.R.E. expedition from the shores of the Antarctic continent, described even 

 larger specimens than had been taken by the Discovery Investigations and was able to 

 give an account of the changes that take place with age. 



NOTOCRINUS MORTENSEN1 John * 



FIGURE 1,6 



Notocrinus, new species, JOHN, Proc. Linn. Soc. London, 1937, sess. 1-19, pt.2, pp. 86,88. 



Notocrinus mortenseni JOHN, Discovery Reports, vol. 18, 1938, pp.123 (listed), 124, 125, 127, 128, 129, 



131, 132 (in key), 194 (localities; description; notes and comparisons); text-figs. 20, a-g, p. 196; 



pi. 6, fig. 2; Rep. B.A.N.Z. Antarctic Res. Exped. 1929-1931, ser. B. vol. 4, pt. 6, 1939, p. 191 



(listed), pp. 209-211 (stations; supplementary description), fig. 7. 



Diagnostic features. The conical or hemispherical centrodorsal is usually lower 

 than wide, with additional cirrus sockets (except in immature specimens) in the radial 

 areas between the regular columns; the cirri are up to LX in number, with up to 40 

 segments; at an arm length of about 105 mm. they are only 25 mm. long. 



Description. The centrodorsal may be conical or hemispherical, with a bare and 

 smooth dorsal pole. The proximal border is produced interradially into small corners 

 or low and wide projections. In some of the younger individuals the corners are raised 

 into ridges free of cirrus sockets; in the others, and in the older ones, they are occupied, 

 like the rest of the centrodorsal, with closely placed cirrus sockets. 



The cirri are XXXVIII-LX or more, 21-32, 20-25 mm. long, composed of stout 



*See also Addenda (p. 836) under 1963. 



