176 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



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

 notes on four of Carpenter's specimens of Antedon gracilis that I had examined. In 

 1915 I again listed Thalassometra pubescens as a southern Japanese species, and dis- 

 cussed the significance of its rango. In my memoir on the unstalked crinoids of the 

 Siboga expdeition published in 1918 pubescens and pergracilis were included in the key 

 to the species of the genus Tlialassometra; pergracilis was given among the species with 

 the cirri arranged, more or less regularly, in 15 crowded columns, while pubescens was 

 given among those in which the cirri are arranged in 10 definite columns. Thalassometra 

 pubescens and Til. pergracilis were listed, and the synonymy and range of each were 

 given. I said that "I am now convinced that the specimen from the Andaman Islands 

 in about 485 fathoms of water which I recorded as Tlialassometra pergracilis does not in 

 reality represent that species. It is in too poor condition for definite determination." 



After examining Carpenter's specimens in the British Museum in August 1925, 

 Prof. Torsten Gisl6n in 1928 noted that the cirri are arranged in 10 columns on the 

 centrodorsal, not in 15 as stated by me in the Siboga report. My statement that the 

 cirri are arranged in 15 columns was based upon Carpenter's figure 4 on plate 12, which 

 clearly shows 3 columns in one radial area, and the same impression is given by figure 1 

 on plate 15. In drawing these animals errors of this sort are easily made unless part of 

 the centrodorsal is denuded of cirri. Gislen pointed out that the name pergracilis 

 suggested by me for this species in 1907 is quite superfluous. He noted that the Antedon 

 (Solanocrinus) gracilis mentioned by de Loriol in 1888 had originally been described as 

 Solanocrinus gracilis by Walther in 1886, so that Antedon gracilis of Carpenter is not 

 preoccupied. Gislen places Walther's Solanocrinus gracilis in the genus Pachyantedon. 



THALASSOMETRA ECHINATA (P. H. Carpenter) 



Antedon echinata P. H. Carpenter, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 119 (de- 

 scription; Challenger station 170A), pi. 21, figs. 4, 5. — Hartladb, Bull. Mus. Comp. Zool., vol. 27, 

 No. 4, 1895, p. 131 (systematic and bathymetrical relationships). — Bather, Geol. Mag., dec. 4, 

 vol. 3, 1897, p. 120 (pinnules compared with those of Millericrinus rectibariensis). — Hutton, 

 Index faunae Novae Zealandiae, 1904, p. 290 (listed). — Hamann, Bronn's Klassen und Ordnungen 

 des Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1578 (listed).— A. H. Clark, Crinoids of the Indian Ocean, 

 1912, p. 33 (of P. H. Carpenter, 1888= Thalassometra echinata). 



Thalassometra echinata A. H. Clark, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 300 (listed); 

 Geogr. Journ., vol. 32, No. 6, 1908, p. 603 (belongs to a group characteristic of the oceanic area) ; 

 Proc. Biol. Soc. Washington, vol. 22, 1909, p. 14 (listed); Crinoids of the Indian Ocean, 1912, 

 p. 208 (synonymy; locality); Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 46 (published 

 reference to specimens in B. M.; Challenger station 170) ; Unstalked crinoids of the Siboga-Kxped., 

 1918, p. 166 (in key; range), p. 171 (references).— Gislen, Ark. Zool., vol. 19, No. 32, Feb. 20, 

 1928, p. 7, No. 26 (notes). 



Diagnostic features.— The cirri have only 25 segments; the elements of the. division 

 series and first two brachials have sharp straight edges fringed with spines, and very 

 narrowly flattened sides; and the cirri are arranged in 10 definite columns on the 

 centrodorsal. The 10 arms are 30 or 35 mm. long. 



Description. — The centrodorsal is low hemispherical. From the figure the cirrus 

 sockets appear to be arranged in 10 columns of usually two each, but the surface of the 

 centrodorsal is not differentiated. 



The cirri are about XX, 25. The fifth segment is the longest, twice as long as 

 broad; the segments in the outer half of the cirri are about as long as broad. The fifth 



