82 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



I wrote that "In the lists of species belonging to the two genera published when I 

 established Thalassometra and Charitometra, orion and compressa were erroneously 

 assigned to the latter." In a revision of the families Thalassometridae and Himero- 

 metridae published on January 9, 1909, I established the new genus Parametra with 

 Antedon orion as the genotype. In a paper on the crinoids of the Zoological Museum 

 at Copenhagen published later in 1909 I recorded a specimen of Parametra orion from 

 near Nagasaki in 170 fathoms and gave notes regarding it. In a preliminary paper on 

 a collection of crinoids made by the United States Fisheries steamer Albatross in the 

 Philippine region published in 1911 I recorded three specimens, all bright yellow, from 

 between Fracas (=Pratas) reef and Formosa. The locality was Albatross station 5306 

 although this was not stated as no station number accompanied the specimens. I 

 wrote that "This species has the division series invariably smooth laterally and without 

 any median carination. It possesses rather fewer arms than P. compressa [=P. granu- 

 lata] and does not reach so large a size." In my memoir on the crinoids of the Indian 

 Ocean published in 1912 I listed Parametra orion, giving the range as southern Japan 

 and southward to Formosa (Taiwan) in 85-170 fathoms. In a paper on some crinoids 

 from eastern Asia collected by Captain Suensson while in command of one of the 

 Danish cable-repair steamers I recorded Parametra orion from south of the Goto Islands 

 hi 223 meters and gave notes on the specimen. In a paper on the distribution of the 

 comatulids of the coasts of China and Japan published in 1915 the bathymetrical and 

 thermal ranges of Parametra orion were given. In my report on the unstalked crinoids 

 of the Siboga expedition published in 1918 I inserted orion in a key to the species of 

 Parametra and gave the geographical and bathymetrical ranges and the synonymy. 



Dr. Theodor Mortensen in a memoir on the development of crinoids published in 

 1920 stated that the eggs of Parametra orion are 0.15 mm. in diameter, only a little 

 smaller than the eggs of Tropiometra carinata, which are 0.2 mm. in diameter. 



In 1922 Prof. Torsten Gislen described Perissometra aranea from a single specimen 

 collected by Dr. SLxten Bock at his station 7a near the Goto Islands and figured a distal 

 pinnule and a cirrus, both of which are typical of this species. He also mentioned 

 specimens in Dr. Mortenseu's collection. In his memoir on the Japanese crinoids 

 collected by Dr. Theodor Mortensen in 1914 he gave notes on three specimens of 

 Perissometra aranea from station 7, which is the same locality as Bock's station 7a, 

 and figured a P! from one of them. He also described Perissometra carinata from 

 two specimens from station 9, figuring the centrodorsal and cirri and the second-fifth 

 brachials with PI and P 2 , and giving a photograph of the type specimen twice enlarged. 

 In the same memoir Professor Gislen described Monachometra mortenseni from 12 

 specimens from station 9, and figured a cirrus and the lower part of an arm with P] 

 and P 2 . 



It is, perhaps, only fair to Professor Gislen to say that the description of Perissometra 

 aranea, P. carinata, and Monachometra mortenseni, all based upon immature individuals 

 of Parametra orion should not be regarded as any reflection on him. The available 

 description of P. orion was poor and deficient in several important respects, and it had 

 not been figured. Superficially Parametra orion certainly resembles some species of 

 Charitometridae more closely than it does most of the species of Thalassometridae. 

 Everyone who has worked with the comatulids has made similar slips, and personally 

 I have been guilty of some much more serious ones. 



