A MONOGRAPH OF THE EXISTING CRINOIDS 207 



and third are about as long as broad, and those following gradually increase in length, 

 becoming about twice as long as broad distally, but shorter again terminally. Pj is 

 5 mm. long, stouter and stilTer than P,, and is the largest pinnule on the arm. It is 

 composed of 11 or 12 segments of which the first is about twice as broad as long, 

 the second is almost or quite as long as broad, and those following gradually increase 

 in length, being twice as long as broad in the distal half of the pinnule. The distal 

 edges of the second and following segments are slightly everted and finely spinous, and 

 the dorsal distal angles are produced in the form of a short blunt process tipped with a 

 tuft of fine spines. P3 is 3 mm. long with about 12 segments proportioned as are those 

 of P2. The pumule is slightly less stout basaUy than P,, and is shorter, weaker, and 

 more slender than that pinnule. The pinnules following are similar, soon gradually 

 increasing in length and becoming more slender. The distal pinnules are about 6 mm. 

 long, composed of about 18 much elongated segments, and exceedmgly slender. The 

 color in alcohol is light yellowish with the elements of the IBr series, a narrow band at 

 the level of the second syzygy, and a few ill-defined bands in the distal portion of the 

 arms, purple. The perisome is brown, and the cirri and Pa are straw yellow. 



The specimen from FadifFolu, Maldives, has the arms .30 mm. long. The cirri 

 have 15 segments. P2 is slender, not greatly longer than Pi, and is composed of elon- 

 gated segments with overlapping distal ends. Pi is longer than P3 and the following 

 pinnules. 



The three specimens from Muhlos, Maldives, have an arm length of from 55 to 

 60 mm. The cirri are XIV, 15, rather slender. Pi is about two-thirds as long as Pj, 

 and is much more slender and less stiffened. P2 is long, but comparatively slender; 

 it is composed of 12 segments of which the distal are twice as long as broad and have 

 projecting distal edges. P3 and the piimules following are shorter than Pi. 



Localities.- — Bagamoyo, Tanganyika Territory (formerly German East Africa), 

 26 miles from Zanzibar (lat. 6° 27' S., long. 38° 55' E.) [A. H. Clark, 1911, 1912, 1918; 

 Hartmeyer, 1916] (3, U. S. N. M., 35385; Berl. M., 6382 [4616]). 



Mauritius; Prof. Karl Mobius [A. H. Clark, 1911, 1912, 1918] (1, Berl. M., 4995 

 [5349]). 



Fadiffolu, Maldive Islands; Prof. J. Stanley Gardiner [Bell, 1902; A. H. Clark, 

 1912, 1913] (1, B. M.). 



Muhlos, Maldive Islands [A. H. Clark, 1912, 1913] (3, B. M.). 



Investigator; ?India (probably Ceylon) [A. H. Clark, 1912] (1, I. M.). 



Geographical range. — From Bagamoyo and Mauritius to the Maldive Islands, 

 and probably to Ceylon. 



Bathymetrical range.- — Littoral. 



History. — Specimens of this species were first mentioned b}' Prof. F. Jeffrey Bell 

 who in 1902 recorded some that had been collected by Prof. J. Stanley Gardiner at 

 Fadiffolu in the Maldive Islands under the name of Antedon laet>issima. 



In a paper on the crinoids of the coasts of Africa published in 1911 I described 

 Decametra mobiusi from a single specimen from Mauritius, and on the following page 

 described D. modica from three specimens from Bagamoyo. In a paper on a small 

 collection of crinoids from the Indian Ocean published in July 1912, I recorded 

 Decametra moebiusi from ?India without comment. In a paper on the crinoids of the 

 Berlin Museum published on November 20, 1912, I hsted the specimens of Decametra 



