A MONOGRAPH OF THE EXISTING CRINOIDS 191 



History. — This species was first mentioned under the name Antedon duplex, a 

 nomen nudum, by Prof. Ludwig von Graff who in 1883 listed it, as a host for myzos- 

 tomes, from off St. Vincent in 124 fathoms (Blake station 269). Professor von Graff 

 republished this notice in 1884. 



Dr. P. H. Carpenter in the Challenger report upon the comatulids published in 

 1888 did not formally describe this species, though he mentioned it several times. 

 He listed it as one of the few species having either 10 or more than 10 arms with the 

 IIBr series 2, and inserted it in his key to the species of the Spinifera group with the 

 characters over 30 cirrus segments, the later ones spiny; Pi as long as or longer than P 2 ; 

 centrodorsal rounded, the cirri without definite arrangement; 30-40 cirrus segments; 

 the IBr axillaries long; and the lower segments of the genital pinnules expanded. He 

 said that Antedon (Stiremetra) lusitanica differs from duplex in the shape of the axillaries 

 and in the unmodified character of the genital pinnules, so far as can be determined 

 from the condition of their fragmentary remains. He gave as the range "Caribbean 

 Islands; Straits of Florida; 88-262 fathoms." 



In 1895 Dr. Clemens Hartlaub discussed the systematic and bathymetrical rela- 

 tionships of this species, on the basis of the information given in the Challenger report, 

 and compared it with his new species Antedon (Thalassometra) agassizii. 



In 1905 Dr. Wilhelm Minckert discussed the syzygies and arm division of Antedon 

 duplex, his specimens, received from Hartlaub, presumably having come from Blake 



station 232. 



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

 to the new genus Thalassometra. In a revision of the family Thalassometridae pub- 

 lished in 1909 I listed Antedon duplex among the species I was unable to place definitely 

 because of lack of material for comparison. In his memoir on the comatulids of the 

 Blake expeditions published in 1912 Hartlaub discussed this species in detail and figured 

 it on the basis of three specimens from station 232. In my memoir on the crinoids of 

 the Siboga expedition published in 1918 I listed Horaeometra duplex and gave the 

 synonymy. I also inserted the new species koehleri in my key to the species of Cosmio- 

 metra, basing this new species on Hartlaub's figures 2 and 4 on plate 3, and 5 and 10 on 

 plate 14, identified by him as duplex. These figures really represent Horaeometra 

 duplex and not a species of Cosmiometra. In 1923 in my memoir on the crinoids of the 

 Ingolj expedition I included Horaeometra duplex and gave the geographical and bathy- 

 metrical ranges. 



In 1941 Dr. Hubert Lyman Clark recorded 42 specimens of Horaeometra duplex 

 from 9 Atlantis stations and some other localities off the coast of Cuba in 145-240, and 

 about 100, fathoms. 



Family CHARITOMETRIDAE A. H. Clark 



Basicurva group (in part) P. H. Carpenter, Challenger Reports, Zoology, vol. 26, pt. 60, 18S8, p. 

 102 (Antedon basicurva, A. incisa, A. luberosa, A. parvipinna, A. flexilis, and A. aculcata); 

 Journ Linn Soc (Zool.), vol. 21, 1889, p. 308 (species compared with Antedon [Pontiometra] 

 andersoni) .-Hartlaub, Nova Acta Acad. German., vol. 58, No. 1, 1891, p. 12 (diagnosis; 

 range- 20 species), p. 14 (characteristic of the deep sea); Bull. Mus. Comp. Zool., vol. 27, 

 No 4 1895 p 130 (revision, and arrangement of the included species according to 

 depth),' p. 136 (structural position).— Bather, Geol. Mag., dec. 4, vol. 3, 1S97, P 120 (pin- 

 nules compared with those of Millericrinus recubariensis) . -Grieg, Bergens Mus. Aarbog for 

 1903 (1904), No. 5, p. 35.— Bell, Marine investigations in South Africa, vol. 4, 190o, p. Ida 



