PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 93 



The cirri are XV-XX, 10-15, about 5 mm. long, strongly recm-ved in tho outer 

 half and resembling those of Antedon petasus. The first segment is very short, the 

 second is about twice as broad as long, the third is sUghtly longer than broad, and 

 the fourth and fifth and following are about a third again as long as the median breadth. 

 The third to fifth arc strongly and rather abruptly constricted centrally, but the seventh 

 and following have tho dorsal and ventral profiles almost straight and hence appear 

 broader in lateral view. On the outer cirrus segments the distal border runs from 

 the ventral edge downward to a rather sharp angle about one third the distance to the 

 dorsal edge, then curves pro.ximally and then downward, joining tho dorsal edge 

 perpendicularly. The opposing spino is prominent, though small. 



The radials are just visible in the midradial line beyond the edge of the centro- 

 dorsal; their interradial angles are shghtly divergent, so that the bases of the IBr, are 

 well separated. The IBri are about twice as broad as long with the lateral borders 

 sUghtly convergent. The IBr2 (axillaries) are pentagonal, about as long as broad, 

 with unusually long sides, about as long as those of the IBri, with which they make 

 a very obtuse angle. Tho IBr series are narrow and very widely separated. 



The 10 arms are about 30 mm. long, with about 50 brachials, which are relatively 

 long and somewhat constricted centrally with spinous ends. 



Syzygics occur between brachials 3+4, 9 + 10, 14 + 15, and distally at intervals of 

 3 muscular articulations. 



Pi is 3 mm. long and is composed of about 18 segments. It decreases rather 

 rapidly in width to tho fomlh segment and is slender from that point onward. The 

 first four segments are broader than long with the corners cut away, and tho remainder 

 are relatively short, not over twice as long as broad. The lower segments have spinous 

 distal ends. Pj is similar but shghtly longer and tapering more gradually. P3 and 

 the following pinnules appear to be shghtly longer than P2 and as they taper more 

 gradually they appear stouter. 



The color in alcohol is pinkish, light bro^vnish, or duU white, with the perisome 

 brown. 



Localities. — Albatross station 3725; Sagami Bay; Noma Saki bearing N. 18° E., 

 8.8 miles distant; 24 meters; sand, shells and gravel; May 15, 1900 [A. H. Clark, 1907] 

 (6, U.S.N.M., 22661, 35701). Type locahty. 



Albatross station 3726; Sagami Bay; Takamatsu Zaki bearing N. 5° W., 5.7 miles 

 distant; 47 meters; gray volcanic sand; May 15, 1900 (4, U.S.N.M., 35696). 



Geographical range. — Known only from the Sagami Bay area, Japan. 



Bathymetrical range. — From 24 to 47 meters. 



History. — This species was dredged by the Albatross in 1900 and was represented 

 in tho collections from that cruise which were sent to Dr. H. L. Clark and subsequently 

 turned over to me by him. He had already recognized it as a new type, and I found 

 the specimens labeled Antedon minuta H. L. Clark, a name which from its appropriate- 

 ness I adopted when I described the species in 1907. 



Upon the creation of the genus Iridometra in 1908 I placed this species in it, and 

 in 1918 I reduced it to the synonymy of Iridometra adrestine. 



Dr. T. Gislen pointed out in 1922 that this disposition was certainly incorrect 

 on tho grounds of the characters of Pj. A reexamination of the material showed that 

 while the specimen I had studied when I had assigned this species to the synonymy of 

 /. adrestine was undoubtedly a young example of that form, the type specimen was 



