A MONOGRAPH OF THE EXISTING CRINOIDS 235 



not always, bilobed, 2-pointed, or replaced by a pair of tubercles. P 2 is usually 

 large, broad, and much flattened; the segments have the distal edges prominent, and 

 there are prominent processes at the distal ends of the prismatic ridges. Rarely P 2 is 

 rather slender, flexible, and almost smooth, or with a long, broad, and sharp spine 

 directed diagonally forward with the tip curved slightly distally, situated on the 

 distal edge of the segments on the side toward the arm tip. 



Although this form has certain features, such as the short cirrus segments of 

 which the distal usually bear paired processes dorsally and the absence of P a , which 

 would appear to place it in the genus Decametra, the characteristic P 2 shows that it is 

 really only an extreme variety of Oligometra serripinna which occurs with it, and 

 with which it intergrades. 



Localities. Danish Expedition to the Kei Islands; Dr. Th. Mortensen; Vatek 

 van Toeal; about 2 meters; rocky coast; March 23, 1922 (1). 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; Vatek van Toeal; 

 about 1-2 meters; rocky coast; March 27, 1922 (23). 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; station 11; 20 meters; 

 sand; April 9, 1922 (1). 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; station 14; about 

 40 meters; sand; April 10, 1922 (7). 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; station 18; about 

 40 meters; sand and coral; April 12, 1922 (2). 



Danish Expedition to the Kei Islands, Dr. Th. Mortensen; station 31; about 

 50 meters; sand; April 19, 1922 (4). 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; station 36; about 

 35 meters; sand; April 23, 1922 (1). 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; station 38; about 

 35 meters; sand, April 24, 1922 (9). 



Danish Expedition to the Kei Islands, Dr. Th. Mortensen, Amboina Bay, 

 about 50 meters, stones and sand, March 2, 1922 (2). 



Nuhu Tawun, northern coast of Little Kei, Kei Islands, Dr. H. Merton, June 16, 

 1908 [Reichensperger, 1913]. 



Ternate; pier, 4 meters; Willebrord Snellius, April 1, 1930 [A. H. Clark, 1936] 

 (4, L. M.). 



Ternate; 2-4 meters; Willebrord Snellius, June 6, 1930 [A. H. Clark, 1936] (12, 

 L. M.). 



Geographical range. Only known from the Kei Islands, Ternate, and Amboina. 



Bathymetrical range. From the shore line down to 50 meters. 



History. The exceptionally large specimens of Oligometra serripinna from the 

 Kei Islands mentioned by Reichensperger in 1913 undoubtedly represent this form. 

 I first met with it when studying the crinoids collected by Dr. Th. Mortensen at the 

 Kei Islands in 1922. It was at that time described in manuscript as Decametra 

 macrobrachius, which was assumed to be a form intermediate between Decametra and 

 Oligometra. It was again found in the collections of the Dutch steamer Willebrord 

 Snellius, and after further study was described in 1936 as Oligometra serripinna var. 

 macrobrachius. 



