172 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



AMPHIOPLUS CONDUCTUS, new species. 



Plate 67, figs. 4-6. 



Locality. — Albatross station 5410; between Cebu and Leyte; Baga- 

 cay Point Light bearing S. 37° W., 13.34 kilometers (7.2 miles) dis- 

 tant (lat. 10° 28' 45" N., long. 124° 05' 30" E.) ; 704 meters (385 

 fathoms) ; March 18, 1909 ; gn. M. 



One specimen (Cat. No. 41161, U.S.N.M.). 



Description. — The specimen is in fairly good condition, although 

 none of the arms are complete ; one of them is preserved for a length 

 of almost 60 mm. The arms must be very long; they are slender 

 and narrow, and maintain the . same width throughout the entire 

 remaining portions. 



The diameter of the disk is 6 mm. ; the disk is rounded. The dorsal 

 and ventral surfaces are slightly convex, and the borders are thin. 

 The dorsal surface is uniformly covered with almost equal plates, a 

 little larger in the central region and in the vicinity of the radial 

 shields, a little smaller in the middle of the interradial spaces and 

 at the periphery of the disk. The radial shields are rather narrow, 

 elongated, at least three times as long as broad, with a straight in- 

 ternal border and a slightly convex external border ; the two shields 

 of each pair are in contact only by their external right angle; in- 

 wardly they diverge rather slowly. Their length is less than half 

 the radius of the disk. 



The ventral surface is uniformly covered with thin, rounded, equal 

 plates, almost as long as broad, imbricated, and becoming more closely 

 crowded in the vicinity of the mouth shields and of the genital slits. 

 These last are broad and very evident. 



The mouth shields are cordiform, almost as broad as long, with a 

 major portion triangular, bounded by two convex sides passing over 

 a rather open proximal angle, and a distal lobe which is broader 

 than long and rounded. The adoral plates are triangular, broader 

 outwardly than inwardly, always in contact in the interradial median 

 line by a small straight side, and giving off outwardly a process which 

 separates the mouth shield from the first side arm plate. The oral 

 plates, which are of medium size, are half again as high as broad. 

 The mouth papillae are four in number. The internal papilla is 

 broadened, rectangular, a little longer than broad, with the proximal 

 border rounded or in the form of a very blunted point; the three 

 others are conical ; the second papilla is the smallest, while the two 

 external are larger and subequal; they are inserted on the adoral 

 plate. Below the second papilla may be seen the elongated and spini- 

 form tentacle scale of the first mouth pore. 



The upper arm plates are large and cover the greater part of the 

 dorsal surface of the arms; they are almost semicircular, with the 



