PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 339 



and in 1937 that "it is quite likely that these will prove to represent the present species 

 [F. mawaoni]." [Note by A.M.C.] The second suggestion was confirmed by Dr. Dilwyn 

 John m 193S. 



In 1915 I recorded and figured what I considered at the time to be a half -grown 

 indi\-idual of Promachocrinus kergueknsis, with 5 rays and 10 arms which had been 

 dredged by the Gau-^s in 222 fathoms (400 meters) in the vicinity of Gaussberg. In 

 tliis specimen the cirri were said to be 52 mm. long with 33 to 37 segments. The 

 centrodorsal is conical, 4 mm. l)road at the base and 4 mm. high, and sliows no resorp- 

 tion at the dorsal pole. The dorsal surface of the earlier brachials is thicldy beset with 

 fine spines. 



This specimen was figured natural size (fig. la) and also twice natural size (fig. 16). 

 The original photograplis were not very clear, and the background was blocked out by 

 myself. While the larger figure does not show the scalloped profile so characteristic 

 of the arm bases of this species, this is indicated in the smaller figure on tlie left side, 

 so that it may have been inadvertently obliterated in the larger figure in the blocldng- 

 out process. 



I am now inclined to believe that this so-called 5-rayed indi^adual of Proma- 

 chocrinus kerguelensis is in reality a specimen of Florometra mawsoni, and that the 

 cirri described (52 mm. in length with 33 to 37 segments) may have come from a 

 different individual. 



[Notes by A.M.C] Mr. Clark also left a comment concerning the resemblance of 

 this species to the smaller Challenger specimens of Solanometra aniarctica from station 

 150 off Heard Island which were named Aniedon australis by Carpenter. Mr. Clark 

 remarked that mawsoni is distinguished by the prominent eversion of the lower brachials 

 and by the relatively longer brachials and axillaries. 



The abundant collections of the Discovery Investigations and B.A.N.Z.A.R.E. led 

 Dr. Dilwjm John to the conclusion that specimens which have the proximal brachials 

 almost smooth (called Florometra antarctica by liim at first) are not specifically distinct 

 from those \vith strong ornamentation of the brachials, intermediate forms having been 

 found. As for the relative wndth of the brachials, this depends to some extent on the 

 size of the specimen, the width tending to increase with absolute size. In the largest 

 t3'pe specimen of australis, with arms about 90 mm. long, the length from the IBri to 

 the second syzygy is 12.5 ram. and the \vidth at the first syzj-gy is 2.0 mm., just as in 

 the fourth specimen of mawsoni in table 9 above. However, in larger specimens 

 there is some divergence since none of the four specimens of mawsoni in the table which 

 have the length to the second syzygy 15 mm. or more have the width over 2.5 mm., 

 whereas in the types of Solanometra antarctica where the length is 15 or 16 ram. tlie 

 width is 3.2 to 3.3 mra. Two large specimens from off Adelie Land naraed S. antarctica 

 by Mr. Clark have the length 17.5 to 19 ram. when the width is 3.0 to 3.2 mra. (see 

 table 12, p. 426), but I am inclined to think that these should have been referred rather 

 to F. 7nawsoni. 



There are other points of resemblance between the types of australis and specimens 

 of mawsoni of comparable size. In the former the cirri have up to 30 segments accord- 

 ing to Carpenter (though all the cirri are now lost from the largest of the three). The 

 longest segments are about two and a half times their proximal widtiis, as in maivsoni 

 and there are well developed dorsal spines on the distal segments in both (see 

 fig. 18, p. 422). P] in the largest australis has about 38 segments and measures 14 mm. 



55G-C22— 6T 23 



