112 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The third specimen from Siboga station 231 is small with 10 arms 55 mm. long. 



Of the three specimens from Siboga station 50 one has 11 arms 85 mm. long. 

 One IIBrI series is present, the IIBr axillary being supported equally by the IBr 

 axillary and by the outer side of the IBr^ Another has 10 arms 85 mm. long, and 

 the cirri 13 mm. long with 20-22 segments. The dorsal pole of the centrodorsal is 

 circular, slightly concave, 2 mm. in diameter. The cirrus sockets are arranged in a 

 single regular crowded row. The color is dark brown, with the cirri and centrodorsal 

 light yellow-brown and the IBr series and first bracbials white; there are one or two 

 distinct white patches on individual arms. The third specimen has 10 arms 85 mm. 

 long. The cirri are VII, 19-20, 12 mm. long. The dorsal pole of the centrodorsal 

 is slightly concave, circular, 2 mm. in diameter. The cirrus sockets are arranged 

 in a single perfectly regular crowded row. 



These three specimens from Siboga station 50 differ from the large individual 

 from station 231 in having slightly fewer cirrus segments, and in having P 3 propor- 

 tionately smaller; but both these differences are directly correlated with the 

 smaller size. 



Localities. Amboina; Dr. J. Brock [Hartlaub, 1890, 1891; A. H. Clark, 1907, 

 1909, 1912, 1913, 1918]. 



Siboga station 231 ; Amboina; anchorage; 40 meters; coral sand; November 14-18, 

 1899 [A. H. Clark] (3, U. S. N. M., E. 419; Amsterdam Mus.). 



Siboga station 50; Bay of Badjo, western coast of Flores; 40 meters; mud, sand 

 and shells; April 16-18, 1899 [A. H. Clark, 1918] (3 Amsterdam Mus.). 



Geographical range. From Amboina to Flores. 



Bathymetrical range. From shallow water down to 40 meters. 



History. This species was described by Dr. Clemens Hartlaub in 1890 from a 

 specimen from Amboina that had been collected in 1884-85 by Dr. J. Brock. It 

 was redescribed and figured by him in 1891. 



In a paper published in 1907 I included Antedon clarae in the synonymy of Car- 

 penter's Antedon manca, but in a revision of the family Himerometridae (as then 

 understood) published in 1909 I listed it as a separate species under the name Cyllo- 

 metra clarae. In my memoir on the crinoids of the Indian Ocean published in 1912 

 I listed Cyllometra clarae and gave the synonymy and habitat. In a paper on the 

 crinoids of the Hamburg Museum published in 1912 I established the new genus 

 Petasometra, based upon a new species, P. helianthoides. To this new genus I referred 

 Antedon clarae, comparing it with the new species. The comparison between Petaso- 

 metra helianthoides and P. clarae was repeated in my memoir on the crinoids collected 

 by the Hamburg Southwest Australian Expedition published in 1913. In my memoir 

 on the crinoids of the Siboga expedition published in 1918 I recorded Petasometra 

 clarae from stations 50 and 231 and gave notes on the specimens. 



ALISOMETRA, new genus 



Otigometra (part) A. H. CLARK, Proc. U. S. Nat. Mus., vol. 34, 1908, p. 308; Proc. Biol. Soc. Washing- 

 ton, vol. 22, 1909, p. 42; Proc. U. S. Nat. Mus., vol. 39, 1911, p. 544; Crinoids of the Indian 

 Ocean, 1912, p. 175. 



Cnlobometra (Prometra) (part) A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 322. 



Prome.tra (part) A. H. CLARK, Journ. Washington Acad. Sci., vol. 5, No. 6, 1915, p. 214; Proc. Biol. 



