A MONOGRAPH OF THE EXISTING CRINOIDS 471 



p. 40 (in key).- HAMANN, Bronns Klassen und Ordnungen des Tier-Reichs, vol. 2, Abt. 3, 1907, 

 p. 1581 (listed). CHADWICK, in Herdman, Report Ceylon Pearl Oyster Fisheries, pt. 2, Suppl 

 Rep. 11, 1904, p. 156 (compared with A. okelli). A. H. CLARK, Crinoids of the Indian Ocean, 

 1912, p. 34 (identity). 



Himerometra regalis A. H. CLARK, Smithsonian Misc. Coll., vol. 50, 1907, p. 356 (listed); Proc. Biol. 

 Soc. Washington, vol. 21, 1908, p. 222 (comparison with H. grandis). 



Dichromctra regalis A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 13 (listed); Crinoids 

 of the Indian Ocean, 1912, p. 34 (identity), p. 150 (synonymy; Tonga Islands). 



Liparometra regalis A. H. CLAEK, Proc. Biol. Soc. Washington, vol. 26, 1913, p. 143 (listed); Smith- 

 sonian Misc. Coll., vol. 61, No. 15, 1913, p. 31 (published references to the specimen in the B. M.; 

 locality; comparison with L. grandis); Unstalked crinoids of the Siboga Exped., 1918, p. 103 

 (in key; range). 



Diagnostic features. The cirri are rather short and stout, with 25-30 segments, of 

 which the longest proximal are not longer than broad and the distal are dorsally cari- 

 nate; P 2 and P 3 are about twice as long as PI, 15 mm. long, with about 30 segments; 

 P 4 is about as long as P : , with 15 segments; the 27 arms are about 150 mm. long. 



Description. The centrodorsal is a thick disk. 



The cirri are about XL, 25-30. The middle and outer segments are somewhat 

 compressed laterally, developing a bluntly pointed keel, which passes into the dorsal 

 spine of the penultimate. 



The anterolateral angles of the radials are just visible. The IB^ are short and 

 are partially united laterally. The IBr 2 (axillaries) are broad, more than twice the 

 length of the IBri, and are almost triangular. The postradial series may divide three 

 times. All the division series are 2. The first few ossicles above the IBr axillary on 

 the outer sides of the postradial series have their outer edges curved and folded, while 

 the lower brachials, both of the inner and of the outer arms, have then- apposed sides 

 flattened against one another. 



The 27 arms are about 150 mm. long. They are long and tapering and consist of 

 about 180 brachials, of which the lower ones are discoidal and their successors are 

 shortly triangular, becoming more quadrate in the middle of the arm and in the termi- 

 nal third more nearly square, elongating slightly toward the arm tip. 



The first syzygy is between brachials 3+4, the second from between brachials 

 16 + 17 to between brachials 19 + 20, and the distal intersyzygial interval is 9 to 19 

 muscular articulations. 



On the outer side of the postradial series P t may reach 8 mm. in length, with 27 

 segments, but on the inner arms it is generally somewhat smaller. P a is about equal 

 to PI. P 2 is also rather larger on the outer than on the inner arms, reaching 15 mm. 

 in length and consisting of about 30 segments, of which the first third are moderately 

 stout and the remainder more slender and somewhat elongated. The pinnules of the 

 next three brachials (P b , PS, and P c ) are of nearly equal size, but P 4 and P d are only 

 about half their length, with 15 segments, and the pinnules of the next pan- are still 

 smaller. 



The disk is 20 mm. in diameter and is naked and much incised. Sacculi are 

 abundant along the sides of the pinnule ambulacra. 



The color in alcohol is dark purple, with greenish white spots on the disk. 



Notes. The preceding description is adapted from the original description of 

 Carpenter. In 1910 I examined the type specimen hi the British Museum. This 



