246 PROCEEDINGS OF THE NATIONAL MUSEUM VOL.83 



Genus COMPSOMETRA A. H. Clark 



COMPSOMETRA NUTTINGI. new species 



Antedon hagenii (part) P. H. Carpenter, Bull. Mus. Comp. Zool., vol. 9, no. 4, 

 pp. 154-156 (pp. 4r-6 of separate), 1881 (Dominica to Grenada; 75-291 

 fathoms; Barbados; Grenada). 



Antedon hageni (part) P. H. Carpenter, Challenger Reports, Zoology, vol. 26, 

 pt. 60, pp. 22, 54, 207, 367, 368, 373, 377, 1888 (Caribbean Islands).— A. 

 Agassiz, Bull. Mus. Comp. Zool., vol. 15 (reprinted as "Three Cruises of 

 the Blake"), pt. 2, p. 124, 1888 (Dominica to Grenada; 75-291 fathoms). 



Coccometra hagenii (part) A. H. Clark, Univ. Iowa Studies in Nat. Hist., vol. 9, 

 no. 5, pp. 8, 26, 27, 1921. 



Description. — The centrodorsal is hemispherical, or low and 

 broadly rounded conical, with a broad area free of cirri and covered 

 with relatively large papillae from the center of which the low, 

 rounded, conical, dorsal pole protrudes. 



The cirri are XXV-XXX, 9-11, 3.5 to 5 mm long. The first 

 segment is not so long as broad; the second is longer than broad, 

 strongly constricted centrally with the distal end prominent; the 

 third is about four times as long as the median width with the terminal 

 fourth expanded; the fourth is the longest, about five times as long as 

 the median width; the fifth is about as long as the third; and the 

 sLxth is about three times as long as the median width. The seg- 

 ments following decrease in length to the second before the last, 

 which is twice as long as the median width, the antepenultimate, 

 which is half again as long as broad, and the terminal, which is slightly 

 longer than broad and bears a blunt opposing spine. The distal 

 ends of the third and following segments are expanded and produced 

 all around into a tliin transparent border that overlaps the base of 

 the segments succeeding; this becomes less prominent on the short 

 distal segments. 



The 10 arms are 25 to 40 mm in length. The earlier brachials have 

 the central portion of the distal edge strongly produced and armed 

 with several stout webbed spines. Beyond the second syzygy the 

 brachials are constricted centrally and have produced and spinous 

 distal ends. The distal brachials are much elongated and very 

 strongly constricted centrally; the syzygial unions are also much 

 swollen. 



The distal intersyzygial interval is usually two muscular articu- 

 lations. 



Pi is long and slender, evenly and gradually tapering and becom- 

 ing very delicate distally. It is composed of 18 to 20 segments of 

 which the first is about as long as broad, the second is slightly longer 

 than broad, the third is twice as long as the median width, strongly 

 constricted centrally, and the remainder are much elongated, four or 

 five times as long as the median width, with swollen proximal ends 

 and the distal ends strongly flaring and spinous. 



