472 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



species is much like the Japanese Liparometra grandis, but it is a smaller and in 

 every way more delicate form. There are no spines on the distal cirrus segments. 

 The figure given of it in the Challenger report is excellent. 



It is possible that Liparometra grandis may turn out to be merely the fully 

 developed form of the present species. 



Carpenter said that the fine specimen on which this species is based is not unlike 

 Antedon (Liparometra) articvlata, but it has a smaller number of cirrus segments 

 which have less well defined dorsal spines in fact the spines are hardly anything 

 more than a small pointed process in the middle of the sharp dorsal keel. P 4 is 

 relatively smaller, and the second syzygy is nearer the disk than in the type specimen 

 of articulata, and there are less than 30 arms instead of nearly 40, or even more, as 

 IIIBr axillaries are not always developed, and there are no IVBr series at all. 



Locality. Tongatabu Island, in the southern portion of the Tonga archipelago; 

 reefs; Challenger, 1874 [P. H. Carpenter, 1888; Hartlaub, 1891; Chadwick, 1904; 

 A. H. Clark, 1907, 1908, 1909, 1912, 1913, 1918] (1, B.M.). 



History. This species was first described under the name Antedon regalis by 

 P. H. Carpenter hi 1888 from a single specimen that had been collected by the Challen- 

 ger on the reefs at Tongatabu, the largest of the Tonga Islands, in 1874. 



Hartlaub in 1891 inserted regalis in his key to the species of the Palmata group, 

 using the differential characters that were employed by Carpenter in his key to the 

 species of the same group in 1888. 



Chadwick hi 1904 compared regalis with his new species Antedon okelli (= 

 Lamprometra palmata), and in 1908 I compared it with my new species Himerometra 

 (Liparometra) grandis. 



In my first revision of the old genus Antedon published in 1907, regalis was assigned 

 to the nw genus Himerometra, and in my revision of the family Himerometridae pub- 

 lished in 1909 it was transferred to the new genus Dichrometra. 



In my memoir on the crinoids of the Indian Ocean published hi 1912 I listed 

 Dichrometra regalis and gave the synonymy and habitat. 



In my revision of the family Mariametridae published in 1913 I placed regalis in 

 the new genus Liparometra. 



In a paper on the crinoids of the British Museum published in 1913 I gave notes on 

 the type specimen, and in a memoir on the unstalked crinoids collected by the Siboga 

 published hi 1918 I inserted regalis in the key to the species of the genus Liparometra. 



Genus LAMPROMETRA A. H. Clark 



Comatula (part) LEUCKART, Zeitschr. ftir organ. Physik, vol. 3, Heft 4, 1833, p. 387. 



Alecto (part) J. MULLER, Monatsber. preuss. Akad. Wiss., 1841, p. 185. 



Comatula (Alecto) (part) J. MULLER, Abh. preuss. Akad. Wiss., 1847 (1849), p. 261. 



Antedon (part) LUTKEN, Mus. Godeffroy Cat., vol. 5, 1874, p. 190, and following authors. 



Actinometra (part) P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 60. 



Himerometra (part) A. H. CLARK, Smithsonian Misc. Coll., vol. 50, 1907, p. 356. 



Dichrometra (part) A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 13. 



Lamprometra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 26, 1913, p. 142 (in key), p. 143 (diagno- 

 sis; genotype Antedon imparipinna P. H. Carpenter, 1882; range; depth; included forms); 

 Unstalked crinoids of the Siboga-Exped., 1918, p. 98 (in key; range), p. 100 (key to the included 

 species). GISLEN, Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 76. 

 H. L. CLARK, Ann. South African Mus., vol. 13, pt. 7, 1923, p. 233 (questions desirability of 



