H(j I.LETIN 82, UNITED STATES NATIONAL MUSEUM 



plates arc smaller and more irregular than they are in Antedon (Poecilometra) acoela. 

 He figured a aide view of a genital pinnule with its ambulacrum, and the ambulacral 

 skeleton of an arm and the bases of six pinnules. In his report upon the comatulids of 

 of the Challenger expedition published in 1888 he described and figured A. incerta 

 in detail. 



Prof. William Bateson mentioned the abnormal postradial series of the type speci- 

 men in 1894, and in 1895 Dr. Clemens Hartlaub discussed the systematic and bathy- 

 metrical relationships of the species. Capt. Frederick Wollaston Hutton listed Antedon 

 incerta among the echinoderms found in the New Zealand seas in 1904. 



In my firs! revision of the genus Antedon published in 1907 incerta was assigned to 

 the new genus Thalassometra. In my revision of the family Thalassometridae published 

 in 1909 And ilon incerta was listed among the species I was unable to place satisfactorily. 

 In another paper published later in the same year inceiia was referred to the new genus 

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

 Crotalometra incerta was listed and the range and synonymy were given, and in a paper 

 on the crinoids of the British Museum published in 1913 I gave brief notes on the type 

 specimen of Aglaometra incerta, which I had examined in 1910. In my memoir on the 

 unstalked crinoids of the Siboga expedition published in 1918 incerta was included in the 

 key to the species of Aglaometra, and the synoirymy and range were given. 



In 1928, Prof. Torsten Gislen, who had examined the type specimen in 1925, 

 published brief notes on Aglaometra incerta and suggested that perhaps it is a species of 

 Thalassometra. 



AGLAOMETRA PROPINQUA (A. H. Clnrk) 



Plate 15, Figure 47 



Crotalometra propinqua A. H. Clark, Proc. U. S. Nat. Mus., vol. 39, 1911, p. 549 (description; Albatross 

 ion 5424; also stations 5274, 5445); Zool. Anz., vol. 39, No. 11/12, 1912, p. 427 (compared 



with C. sulcata); Crinoids of the Indian Ocean, 1912, p. 209 (synonymy; locality). 

 Crotalometra vera A. H. Clark, Zool. Anz., vol. 39, No. 11/12, 1912, p. 427 (description; Siboga station 



173). 

 Aglaometra vera A. H. Clark, Unstalked crinoids of the Siboga-Exped., 1918, p. 163 (in key; range), 



p. 165 (description; station 173), p. 274 (listed), pi. 21, fig. 54. 

 Aglaometra propinqua A. H. Clark, Unstalked crinoids of the Siboga-Exped., 1918, p. 163 (in key; 



range), p. 165 (references). 



Diagnostic features. — The cirri are rather slender, less than half the arm length; 

 the division series ;wu lower brachials are in close lateral contact; and the proximal 

 portion of the animal is broadly rounded. The 10 arms are 130 mm. long, and the cirri 

 are 4."> 60 inni. long with 59-69 segments. 



Description.- The centrodorsal is moderate in size, conical, the sides slightly con- 

 vex. 5.5 mm. broad at the base and 4.5 mm. high to 4.5 mm. broad at the base and 3.5 

 mni. high, the tip somewhat truncated. The cirrus sockets are arranged in 10 columns, 

 l\\ o or three to a column; the columns are slightly separated in the midradial line and in 

 close apposition interradially. 



The cirri are XX, 59-64, from 45 to 55 mm. long, moderately stout, though not 

 nearly so stout as those <■■( A. , upedata; the first three segments are short, the fourth or 

 fifth as long as broad; the fifth, sixth, or seventh (usually the sixth) is a transition seg- 

 ment, half again - broad. The following segments gradually decrease in length, 

 becoming about as long as broad on the fourteenth-sixteenth, and distally twice as 



