A MONOGRAPH OF THE EXISTING CRINOIDS 115 



History. The type and only known specimen of this species was originally 

 recorded by me under the name Oligometra japonica in a paper published in 1908 

 on the collection of comatulids made by Alan Owston in his yacht the Golden Hind. 



In 1909 I compared the new species Oligometra (Decametra) studeri to various 

 other forms, among which was Oligometra japonica. At that time my conception of 

 0. japonica was based upon the specimen just mentioned. In my memoir on the 

 crinoids of the Indian Ocean published in 1912, in discussing the new species Colobo- 

 metra (Prometra) brevicirra I said, "The only other species [besides C. (P.) chadwicki] 

 with which this needs comparison is C. (P.) owstoni of Japan (Oligometra japonica 

 A. H. Clark, Proc. U. S. Nat. Mus., vol. 34, p. 308; not Antedon japonica Hartlaub, 

 1890), which also has short cirri resembling those of Oligometra serripinna." This 

 is the first mention of the specific name owstoni. In 1915 1 listed Prometra owstoni 

 as a southern Japanese species, and in 1916 described Prometra owstoni as a new 

 species without any reference to a previous mention of the name or of the type speci- 

 men. In my memoir on the unstalked crinoids of the Siboga expedition published 

 in 1918 I included owstoni in the key to the species of the genus Prometra, and com- 

 pared it with Prometra longipinna, new species. 



ALISOMETRA LONGIPINNA (A. H. Clark) 



Oligometra japonica A. H. CLARK, Proc. U. S. Nat. Mus., vol. 39, 1911, p. 544 (Albatross station 



5356); Crinoids of the Indian Ocean, 1912, p. 175 (Philippine record). 

 Prometra longipinna A. H. CLARK, Proc. Biol. Soc. Washington, vol 29, 1916, p. 108 (Philippine 



Islands, 58 fms.; nomen nudum); vol. 31, 1918, p. 37 (description; Albatross station 5356); 



Unstalked crinoids of the Stboja-Exped., 1918, p. 125 (in key; range; description; Albatross 



station 5356). 



Diagnostic features. The cirri have 14 or 15 segments and are about 4 mm. long; 

 P,, P 2 , and P 3 have 11 or 12 segments and are 5 mm. long; the arms are about 30 mm. 

 long. 



Description. The cirri have 14 or 15 segments of which the fourth and following 

 are about as long as broad. The length of the cirri is about 4 mm. 



The arms are about 30 mm. long and resemble those of P. owstoni. 



P, is 5 mm. long, stiff and spine-like, composed of 11 or 12 segments of which the 

 first is broader than long, the second is one-third again as long as broad, and the 

 fourth and following are from two and one-half to three times as long as broad. The 

 terminal 3 or 4 have prominently spinous distal ends. P 2 is 5 mm. long with 11-12 

 segments and exactly resembles P,. P 3 is 5 mm. long with 11 segments of which the 

 distal are slightly more elongate than those of the preceding pinnules, and the fourth 

 and following have everted and spinous distal ends. P 4 and the following pinnules 

 are 3.5 mm. long with 10 segments, smaller and weaker than the pinnules preceding, 

 though the component segments are of about the same proportions; the fourth and 

 following segments have everted and spinous distal ends. The distal pinnules are 

 4.5 mm. long with 14 segments of which the third and following have slightly pro- 

 duced and finely spinous distal ends. 



Locality. Albatross station 5356; North Balabac Strait; Balabac light bearing 

 S. 64 W., 15.5 miles distant flat. 806'40" N., long. 11718'45" E.); 106 meters; 

 sand and shells; January 5, 1909 [A. H. Clark, 1911, 1912, 1916, 1918] (1, U. S. N. M., 

 35366). 



