OPHIUBANS OF UNITED STATES NATIONAL MUSEUM. 29 



and the difTerences which I noted are due very likely to a difference in the ages 

 of the specimeas, Venill's type being larger than the one I have before me, since 

 its disk roaches 9 mm. 



In the specimen from the Blake, the upper plates of the disk are fewer; the 

 centro-dorsal plate is directly in contact ^\^th the five large radial primary 

 plates, without any intercalary plates Ij-ing between them, as stated and figured 

 by Vcrrill. The radial shields of each pair are contiguous on a part of their 

 length and the triangidar plate wliich separates them distally is as long as wide 

 and may even become a httle wider than long. The upper plates of the disk carry 

 fau-ly large granules, but these, instead of being irregidarly scattered over the 

 plates, are located cliiefly toward their external margin, a (Hsposition existing 

 especially on the five radial primary plates; these arrangements give to the upper 

 face of the disk a sUghtly different appearance from that represented by Vcrrill. 

 The characters of the under face of the disk, of the mouth-pieces, and of the arms 

 being altogether in conformity with those indicated by Verrill, I thought my 

 specimen should be referred to the same species. 



OPmOMUSIUM SERRATUM Lyman. 

 Ophiomudum serralum Lymax (82), p. 85. pi. 2, figs. 1-3; pi. 39, fi<». 10. 



Albatross station 2345. Jan. 20, 1885. Lat. 23° 10' 40" N.; lono-. 82° 20' 15" 

 W.; 184 fathoms; fne. gy. wh. co. One specimen. 



OPmOMUSnJM TESTUDO Lyman. 



Plate 3, fig. 7. 



OpMomuaium (eshido Lyman (75), p. 8, pi. 1, figs. C-S. 

 Ophiomusium tesiudo Lyman (78), p. 210. 

 Ophiomimum iestvdo Ly'man (82), p. 99. 

 Ophiomusium testudo Lyilan (83), p. 246. 

 Ophiomusium testudo Verrill (99), p. H. 

 Ophiomusium testudo Kcehler (07), p. 297. 



Albatross station 2342. Jan. 19, 1885. Lat. 23° 10' 39" N.; long. 82° 20' 

 21" W.; 201 fathoms; CO. One specimen. 



The specimen is not altogether in conformity with Lyman's description and 

 drawings; it differs from them chiefly in ha\ing the upper plates of the disk more 

 regularly arranged and fairly equal in size. By these characters, it is closely alUed 

 to two specimens kept at the Jardin des Plantes and collected by the expedi- 

 tion of the Blalce. These specimens, which were given by Agassiz, were certainly 

 determined by Lyman; the diameter of the disk measures, respectively, 6 and 

 6.5 mm. ; they are consequently a httle larger than Lyman's type, the diameter of the 

 disk of which was only 5.5 mm. 



In the specimen from the Albatross, the diameter of the disk reaches 7 mm.; 

 the arms are preserved to a length not exceeduig 10 mm. The disk is pentagonal, 

 with rounded angles. The upper face, fairly convex, is covered with few plates, 

 the size of which is uniform. There is to be seen one large polygonal, centro- 

 dorsal plate, out of which comes a circle of small radial plates, wliich, moreover, 



