A MONOGRAPH OF THE EXISTING CRINOIDS 291 



ventrally. Distally the segments gradually become elongated, so that those in the 

 outer third are twice as long as broad or even longer. Usually one or more of the 

 segments preceding the comb is more or less abruptly elongated, being twice as 

 long as broad, or even longer. The comb is extremely long, usually arising at about, 

 or within, the end of the proximal third of the pinnule, on about the tenth segment. 

 The teeth soon become very long, in the outer half of the comb being two or three 

 times the width of the segments in height. They have moi-e or less parallel sides 

 which are slightly constricted near the base and a broadly and evenly rounded tip. 



Very often, sometimes in as many as half of the total number in an individual, 

 Pi does not bear a comb but simply tapers gradually to a slender pointed tip, being 

 straight and more or less stiffened and composed of progressively elongated segments. 



Pa resembles Pi and may either bear a very long comb or taper gradually to a 

 pointed tip. 



P2 is without a comb. It is straight, shorter than Pi, and tapers to a pointed 

 tip. It is composed of increasingly elongated segments. 



Hartlaub reproduced a figure which was originally drawn for Carpenter showing 

 a pinnule consisting of 21 segments, of which the last 10 bear teeth. The first 

 segment is nearly twice as broad as long, the second is about as long as broad, and 

 those following increase in length so that the last before the comb is about four times 

 as long as broad. Hartlaub believes that this represents Pj, but it is more likely 

 that it represents Pi or Pa of an intermediate type, as in the specimens which I have 

 examined P2 never shows any trace of a comb. 



The following pinnules have the 2 basal segments short and the third and fol- 

 lowing greatly elongated. 



The disk is about 4.5 mm. in diameter. 



The mouth is approximately central. The anal tube is long. Sacculi are abun- 

 dantly developed along the brachial and pinnule ambulacra. 



The color in alcohol is uniform light yellow or yellowish white. 



Notes. — In the 2 large specimens from the Pourtales plateau the cirri are 15 mm. 

 in length and are composed of 18-20 segments. 



Localities. — Fish Hawk station 7302 ; Cape Lookout (North Carolina) Lighthouse 

 bearing E. by N. Ye N., 1?^ miles distant; 14 meters; temperature 27.0° C; hard sand; 

 July 24, 1902 [A. H. Clark, 1918] (1, U.S.N.M., 34634). PI. 6, fig. 20. 



Fish Hawk station 7280; Gulf Stream, off Key West (lat. 24° 17' N., long. 81° 

 58' 25" W.); 241 meters; temperature 11.11° C; February 14, 1902 [A. PI. Clark, 

 1918] (1, U.S.N. M., 34632). 



Fish Hawk station 7298; Gulf Stream, off Key West (lat. 24° 19' 00" N., long. 

 81° 39' 45" W.); 219 meters; bottom temperature 18.5° C. ; coral bottom; February 

 26, 1902 [A. H. Clark, 1918] (1, U.S.N. M., 34628). PI. 6, fig. 19. 



Off Key West, Fla.; about 146 meters (1, M. C. Z., 747). 



Florida Keys; 172-229 meters (1, M. C. Z., 44 [part]). 



University of Iowa's Bahamas expedition station 30; south of Key West; about 

 183 meters [H. L. Clark, 1918] (1, U. I. iM.). 



University of Iowa's Bahamas expedition station 48; southeast of Key West; 

 about 146 meters [H. L. Clark, 1918] (2, U. I. M.). 



