A MONOGRAPH OF THE EXISTING CRINOIDS 213 



of two specimens. In 1894 Prof. F. Jeffrey Bell recorded four specimens from the 

 Sahul Bank, figuring portions of the arms of three of them and the distal portion of 

 the cirri of two. He wrote that he was at first inclined to consider the four specimens 

 which he included under the name Antedon patula as representatives of a new species, 

 but Carpenter's species is founded on two specimens of much the same size, and smaller 

 and younger examples such as he had before him might well have a smaller number 

 of cirri and a less marked development of the ridge on the more distal of the brachials. 

 He noted that Antedon flexilis, A. patula, and A. robusta were all taken at the same 

 station by the Challenger and remarked it is very likely that an increase in our series 

 may show that there are not so many well-marked species as has been supposed. 



In my first revision of the old genus Antedon published in 1907 patula was trans- 

 ferred to the new genus Charitometra, and in the same year it was listed as Antedon 

 patula by Hamann. Upon the establishment of the genus Pachylometra in 1909 

 I transferred it to that genus. In 1911 I recorded and gave notes on three specimens 

 of Pachylometra patula from Albatross station 5356, and in my memoir on the Recent 

 crinoids of Australia I included the record from the Sahul Bank. In my memoir 

 on the crinoids of the Indian Ocean published in 1912 I listed Pachylometra patula, 

 giving the synonymy and locality records, and in the same year Dr. Clemens Hartlaub 

 mentioned Antedon patula in his discussion of the Spinifera-group of the genus Antedon. 

 In 1913 I noted that at the British Museum I had examined two specimens of Pachy- 

 lometra patula from Challenger station 192, and one young specimen from the Sahul 

 Bank recorded as Antedon patula by Bell. A second specimen from the Sahul Bank 

 I identified as Pachylometra robusta. 



In 1914 Prof. Frank Wigglesworth Clarke and Dr. W. C. Wheeler published 

 an analysis of the inorganic constituents of the skeleton of Pachylometra patula; they 

 gave the locality of their material as Albatross station 5036, which is an error for station 

 5356. 



In 1916 I transferred patula to the new genus Perissometra, and in my memoir 

 on the unstalked crinoids of the Siboga Expedition published in 1918 patula was included 

 in the key to the species of Perissometra and the synonymy and range were given. 



In his report on the crinoids collected by Dr. Th. Mortensen in Japan published 

 in 1927 Prof. Torsten Gislen discussed the genera Glyptometra and Perissometra, 

 pointing out the unsatisfactory nature of the supposed differences between them and 

 suggesting that patula should be transferred to Glyptometra. In 1928 he wrote that 

 the two specimens from Challenger station 192, wlu'ch he had examined in the British 

 Museum, represent two widely different forms, one of which ought to be referred to 

 Monachometra. In 1934 he classed the arm division of Perissometra patula with the 

 Asterometra type. 



MONACHOMETRA FLEXII.IS fp. H. Carpenter) 

 [See vol. 1, pt. 2, pi. 44, figs. 1288-1290, 1292.] 



Antedon flexilis VON GRAFF, Challenger Reports, Zoology, vol. 20, pt. 61, 1887, pp. 8, 12 (Challenger 

 station 192; myzostomes; nomen nudum). P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, 

 pt. 60, 1888, pp. 128, 217 (description; Challenger station 192), pi. 42. HARTLAUB, Bull. Mus. 

 Comp. Zool., vol. 27, No. 4, 1895, p. 130 (systematic and bathymetrical relationships), p. 134 (size 

 compared with that of A. [Thalassometra] agassizii [erroneously given as 55 cm. instead of 35 cm.]), 

 p. 135 (compared with A. [Thalassometra] agassizii). MINCKERT, Arch. Naturg., Jahrg. 71, 1905, 



