A MONOGRAPH OF THE EXISTING CRINOIDS 405 



are basaUy united but diverge very rapidly distally. The IBr 2 (axillaries) are pen- 

 tagonal, about half again as broad as long. The IIBr, IIIBr, and IVBr series are 2 

 and are widely separated; the IVBr series are developed only on the outer side of the 

 IIBr series. The 44 arms are 90 mm. long. The first ten brachials are oblong, not 

 quite twice as broad as long, those succeeding are wedge-shaped, almost triangular, 

 about twice as broad as long, becoming proportionately longer in the distal part of 

 the arms. Syzygies occur between brachials 3+4, again from between brachials 

 44+45 to between brachials 56 + 57 (usually nearer the latter), and distally at inter- 

 vals of 6 to 11 (usually 7 to 9) muscular articulations. 



Pj is 10 mm. long, slender but somewhat stiffened, tapering evenly from the base 

 to the delicate tip, composed of 22 segments, of which the first is about twice as 

 broad as long, the fourth is about as long as broad, and those following gradually 

 increase in length so that the seventh and following are about half again as long as 

 broad. P 2 is usually slightly longer than Pj and is composed of 17 segments, of which 

 those in the distal part are more elongated than the corresponding segments in Pi. 

 P 3 is 5.5 mm. long, with 12 segments, and is of the same character as the two preceding 

 pinnules. The following pinnules are small, short, and delicate, 4 mm. long, with 12 

 segments, of which the first three are about as long as broad and the remainder are 

 longer than broad, becoming about twice as long as broad distally. The distal pin- 

 nules are 7 mm. long, with 20 segments of which the first is short, the second is about 

 as long as broad, the third is about half again as long as broad, and the remainder 

 are about twice as long as broad or rather longer. The color in alcohol is brownish 

 gray. 



In the specimen recorded by Koehler from Billiton the cirri reached a length of 60 

 mm. The arms were exactly 40 in number, 100 to 120 mm. long; each postradial 

 series divided regularly three times. Professor Koehler said that this specimen 

 conformed in all respects with Hartlaub's description. 



The specimen from Investigator station 175 was described as a new species under 

 the name of Dichrometra aranea. This new species was said to be nearest O.finschii, 

 differing from that form in having fewer cirrus segments (53-66) and in having P 3 

 nearly or quite as long as P 2 , while the segments in the distal portion of the proximal 

 pinnules are much elongated instead of subequal, slightly longer than broad, as in 

 O. finschii. The lower pinnules are comparatively slender and are only slightly 

 stiffened. P 2 is about as stout as P! and 2 mm. longer. 



Localities. — Albatross station 5413; between Cebu and Bohol, Philippines; Lauis 

 Point light bearing N. 68° W., 10 miles distant (lat. 10°10'35" N., long. 124°03'15" 

 E.) ; 77 meters; March 24, 1909 [A. H. Clark, 1911, 1912, 1918] (1, U. S. N. M., 27491). 



Albatross station 5163; Tawi Tawi group, Sulu (Jolo) archipelago; Observation 

 Island bearing N. 79° W., 6.7 miles distant (lat. 4°59'10" N., long. 119° 51'00" E.); 

 51 meters; coral sand; February 24, 1908 [A. H. Clark, 1908, 1909, 1911, 1912, 1918] 

 (1, U. S. N. M., 25455). 



New Britain; Dr. Otto Finsch [Hartlaub, 1890, 1891; A. H. Clark, 1907, 1909, 

 1911, 1912, 1918; Hartmeyer, 1916] (2, U. S. N. M., 35268; Bed. M., 2602, 2603 [1 

 specimen]). 



Biliton, between southeastern Java and Borneo; M. Korotnev, 1S85 [Koehler, 

 1895]. 



