158 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



the arm spines are six in number. All these characters seem to me to 

 separate the abyssal form found by the Albatross sharply from A. 

 fusco-alba, which is essentially littoral. 



AMPHIURA DIOMEDEAE Liitken and Mortensen. 



Plate 67, figs. 7-10. 



Amphiura diomedeae LUTKEN and MORTEN SEN ('99), p. 151, pi. 12, figs. 

 1-7. H. L. CLARK ('11), p. 140; ('13), p. 214; ('15), p. 225. 



Localities. Albatross station 5111 ; China Sea, off southern Luzon; 

 Sombrero Island bearing S. 41 E., 8.34 kilometers (4.5 miles) dis- 

 tant (lat. 13 45' 15" N., long. 120 46' 30" E.) ; 432 meters (236 

 fathoms) ; January 16, 1908. 



Five specimens (Cat. Nos. 41213, 41214, U.S.N.M.). 



Albatross station 5281; China Sea, in the vicinity of southern 

 Luzon; Malavatuan Island (N.) bearing S. 84 W., 7.97 kilometers 

 (4.3 miles) distant (lat. 13 52' 45" N., long. 120 25' 00" E.) ; 368 

 meters (201 fathoms) ; July 18, 1908; dk. gy. S. 



Two specimens (Cat. No. 41210, U.S.N.M.). 



Albatross station 5325; off northern Luzon; Hermanos Island 

 (N.) bearing N. 86 E., 31.04 kilometers (16.75 miles) distant (lat. 

 18 34' 15" N., long. 121 51' 15" E.) ; 410 meters (224 fathoms) ; 

 November 12, 1908 ; gn. M. 



One specimen (Cat. No. 41211, U.S.N.M.). 



Albatross station 5535; between Cebu and Siquijor; Apo Island 

 (C.) bearing S. 24 W., 31.50 kilometers (17 miles) distant (lat. 9 

 20' 30" N., long. 123 23' 45" E.) ; 567 meters (310 fathoms) ; Au- 

 gust 19, 1909 ; gy. glob. Oz. 



One specimen (Cat. No. 41212, U.S.N.M.). 



Notes. In the largest specimen, which comes from station 5111, 

 the diameter of the disk reaches 8 mm., and the arms are from 28 

 mm. to 30 mm. long. 



I have been able to compare these specimens with a very typical 

 example of A. diomedeae sent to me by the United States National 

 Museum, which was dredged by the Albatross. I show here (pi. 

 67, figs. 7, 8) the two surfaces of this specimen, which I have used 

 for comparison. The specimen from station 5281, in which the 

 diameter of the disk is 6.5 mm., agrees well with it; most of the 

 others agree also, with it but they are very small. 



The largest specimen from station 5111 (figs. 9, 10) differs from 

 this typical specimen in the arrangement of the dorsal plates of 

 the disk which are not imbricated in the central region, but remain 

 rounded, and the primary plates are still fairly distinct. The 

 plates imbricate only toward the periphery of the disk, where they 



