A MONOGRAPH OF THE EXISTING CRINOIDS 265 



[P. H. Carpenter, 1880, 1884, 1888; von Graff, 1884, 1885; Springer, 1901; Minckert, 

 1905; Hamann, 1907; A. H. Clark, 1907, 190S, 1909, 1912, 1913, 1916, 1918; Gislen, 

 1924, 1928, 1934] (5, B.M.). 



History. — Dr. P. H. Carpenter in 1880 published a figure of a plated disk of a 

 comatulid identified only as Antedon, sp. 



In 1884 Prof. Ludwig von Graff described some myzostomes from Antedon angus- 

 ticalyx from Challenger station 214. The name, which had been given him by Dr. 

 P. H. Carpenter, was a nomen nudum. 



In his report on the stalked crinoids of the Challenger Expedition Dr. Carpenter 

 gave a "specific formula" for this species, which is the equivalent of a description. He 

 described the swollen genital pinnules in detail, noting that they receive no branches 

 from the brachial food grooves and lack the ambulacral epithelium, nerves, and blood 

 vessels, whde the water vessels are simple tubes like the integumentary water vessels 

 of the Molpadiidae without lateral extensions, since the tentacles are absent. He 

 remarked that the fertile intrapinnular portions of the gonads are short, thick, and 

 rounded, and that the sacculi occupy little pits in the large plates that cover the ovarian 

 pinnules, and also in the substratum of the small later segments of the pinnules. He 

 said that the ambulacra crossing plated disks are generally marked by an irregular 

 row of transversely oblong plates, as in this species. He gave a figure of an ovarian 

 pinnule and republished the figure of a plated disk published in 1880, identifying it as 

 Antedon angusticalyx. 



Professor von Graff again mentioned the myzostomes of Antedon angusticalyx 

 in 1885. 



In the Challenger report on the comatulids published in 1888 Dr. Carpenter de- 

 scribed Antedon angusticalyx in detail and figured it. Wilhelm Minckert discussed the 

 distribution of the syzygies in this species in 1905. 



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

 assigned to the new genus Charitometra, and as Charitometra angusticalyx it was com- 

 pared with the new species Charitometra smithi in 1908. In 1909 this species was 

 transferred to the new genus Pachylometra, and Pachylometra angusticalyx was com- 

 pared with the new species P. levigata. In the same year the constriction of the proxi- 

 mal portion of this species was compared with a parallel constriction of the proximal 

 portion of Ptilometra splendida. 



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

 angusticalyx was listed and the synonymy and range were given. In 1913 I noted 

 that I had examined five small specimens from Challenger station 214, the type material, 

 in the British Museum. 



In 1916 angusticalyx was transferred to the new genus Perissometra and listed as 

 Perissometra angusticalyx, and in my memoir on the unstalked crinoids of the Siboga 

 Expedition Perissometra angusticalyx was included in a key to the species of that 

 genus, and the synonymy and range were given. 



Prof. Torsten Gislen in 1924 noted that Carpenter in 1884 had pointed out that 

 two representatives of the family Charitometridae, later identified as Poecilometra 

 acoela and Pachylometra angusticalyx, sometimes lack the ambulacral grooves on as 

 many as 20 pairs of proximal pinnules. In 1928 he noted that he had examined the 

 Challenger specimens of Perissometra angusticalyx and that the species should be re- 



