[9] FAUNA OF OUTER BANKS, VINEYARD SOUND, ETC. 649 



concave in the middle, and undulated by several faint broad ribs ; it 

 recedt'S posteriorly, and a broad, concave furrow separates it from the 

 small i)osteriur ijrea, Mhich is without ribs, and has a prominent rounded 

 edge. The surface is tinely granulated, lines of growth evident. The 

 interior is pearly, angulated by a deep groove, corresponduig to the 

 largest external rib. The dorsal hinge-line is nearly straight poste- 

 riorly, and strongly incurved anteriorly, in the right valve it projects 

 inward, but not in the Icit ; in the right valve there is a small rounded 

 tubercle, a little bade of the beak ; from below this a short rib-like 

 process runs back below the deep, partially internal cartilage-pit, which 

 extends forward and upward under the beak as a narrow furrow. An- 

 terior muscular scar deep; i)osterior one larger, ovate, less distinct; 

 sinus small. Length, -?.")""" : height, 2(i '"'" ; breadth from side to side, 



0'> mm 



Station 1)47; 312 fathoms. One pair of fresh valves, dead. 

 This and the ])reccding were both taken by means of the "rake- 

 dredge." 



Drplodonta turf/ifla Verrill and Smith. 



Shell large for the genus, round-ovate, a little longer than high, very 

 swollen ; the two ends nearly equally rounded, the anterior a little nar- 

 rower ; ventral edge broadly and regularly rounded; beaks nearly cen- 

 tral, somewhat forward of the middle, strongly curved iuAvard and for- 

 ward, acute. Surface without sculpture, smooth except for the evident 

 lines of growth. In the right valve there are, opposite the beak, two 

 nearly equal, stout, sharp teeth, separated by a space of about the 

 same width; back of these, and i)artiy joined at base to the posterior 

 one, there is a much larger, broad, stout, obtuse tooth, with a groove 

 on its dorsal side; external cartilage-groove and its lamella are long 

 and narrow, curved. Length, 29"'"' ; height (umbos to ventral edge), 

 25mm. breadth, 23'"'". 



Station 950 ; 09 fathoms. One right valve. 



1882. 



During the summer of 1882 the liead(iuarters of the United States 

 Fish Commission were at Wood's Holl, Mass. The organization of the 

 party was nearly the same as last year.* The special object this year 



"The scientific party associated with the writer in carrying on the dredging opera- 

 tions and making the eolloctions this year consisted of Mr. Eichard Rathbnn, Mr. 

 Sanderson Smith, Mr. J. H. Emerton (as artist), Prof. L. K. I.ee, Mr. B. V. Koons, Mr. 

 H. L. RnuKir, Prof. r>dwin Linton. Prof. S. I. Smith was with ns for a few days. 

 Mr. Pettr Parker and 11. II. Miner, luidshipnieu, U. S. N., took charge of the fishes, 

 JohnB. Blish, midshipman, U. S.N.,kept the records of sonndingsand temperatures, 

 and Capt. H. C. Chester had charge of the dredging apparatus, as in previous years. 

 The drcdgings were all made by the Fish Hawk, commanded by Lieut. Z. L. Tanner, 

 U. S. N., as during the two previous years. The writer, as usual, had general charge 

 of these exploration.s, and of the investigation of the InA^ertebrate fauna. 



