A MONOGRAPH OF THE EXISTING CRINOIDS 



505 



Carpenter said that this species is distinguished from Antedon aequipinna by the 

 great disproportion in the sizes of P 3 and P 4 . It is much more marked than in Antedon 

 laevicirra, which also differs in having more uniform cirrus segments, a longer interval 

 between the first two syzygies, and less marked forward projections on the brachials. 



I examined the type specimen of Antedon imparipinna at the Hamburg Museum 

 in 1910. P 2 on the outer arms is exceptionally long. 



There are two other specimens in the Hamburg Museum without locality. They 

 are both typical. In one of them the proximal pinnules are rather long, and in the 

 other they are rather short. 



Forms. The characters of the several named forms of this species may be appre- 

 ciated by means of the following key. Some of these forms are perhaps worthy of 

 recognition as representing fairly well marked and stable varieties, but most of them 

 represent simply individual variants or growth or developmental stages. 



KEY TO THE NAMED FORMS OF LAMPROMETRA PALMATA 



a 1 . Arms short, composed of about 100 brachials brachypecha (p. 489) 



a 2 . Arms longer, composed of 150-170 brachials. 

 b 1 . Postradial series free laterally. 



c. Lower pinnules larger on outer arms arising from each IIBr axillary than on inner. 



d>. P 3 quite short protecta (p. 488) 



(P. P s not especially short, nearly as long as P 2 on inner arms conjungens (p. 482) 



c 2 . Lower pinnules fairly uniform in size on all the arms. 

 d 1 . P 3 smaller than P 2 ; cirri smooth. 



(aequipinna (p. 502) 

 subtilis (p. 498) 

 okelli (p. 501) 

 e 2 . P 2 larger than P b . 

 /'. PS smaller than PI; second syzygy about the twentieth brachiaL -laevicirra (p. 490) 



f 2 . Pa equal to PI; second syzygy about the thirteenth brachial imparipinna (p. 504) 



Jmoorei(p. 481) 

 d 2 . P 3 almost as long as P 2 ; cirri spiny .. \lepida (p. 487) 



b 2 . Postradial series in close lateral contact. 

 c 1 . Cirri spiny. 



d l . Over 30 cirrus segments; Pj not much smaller than Pj; lower brachials with flattened 



sides gyges (p. 517) 



d 2 . Not over 25 cirrus segments; P! much smaller than P 2 palmata (p. 500) 



c 2 . Cirri carinate, but not spiny. 



d l . No IVBr series; lower brachials flattened laterally; radials visible. 



fbrevicuneata(p. 492) 

 e'. P 4 altogether smaller than P,.. --\amboinensis (p. 493) 



e 2 . P, nearly similar to P 3 similis (p. 485) 



d 2 . IVBr series present; IBr axillaries almost concealed by centrodorsal occulta (p. 486) 



Localities. Hongkong [Hartlaub, 1891; Koehler, 1895; A. H. Clark, 1911, 1912; 

 Mortensen, 1934] (1, H. M.). 



Macclesfield Bank; 24 meters [Bell, 1894; A. H. Clark, 1908, 1912, 1913; Hartlaub, 

 1912] (1, B. M.). 



Macclesfield Bank; 18-24, and 24, meters [A. H. Clark, 1929] (2, B. M.). 



Nha'trang Bay, Annam; 40 meters; Dr. C. Dawydoff, July 14, 1928 [Gisle"n, 

 1936]. 



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