SIS /'/, oc /:/:/> rx< ; x or THE NATIONAL MTSEUM. VOL.XX. 



The following are described species : 



(i. n i fens Jeffreys, North Atlantic (Europe) and from off Marthas 

 Vineyard south to off Kiodela Plata (America); G. jcffreysi Smith; 

 G.*i>n]>l<'.r Smith, and G.inwquilateralis Smith, West Indies; CT. japon- 

 icus Smith, off Japan. 



GLOMUS NITENS Jeffreys. 



(Plate XCVI1, figs. 1,2.) 



(llomns nitens JEFFREYS, Annals Mag. Nat. Hist., p. 433, November, 1876; Proc. 

 Zot'il. Soc., London, p. 573, pi. XLV, fig. 5, June, 1879. VERRILL, Trans. Conn. 

 Arad.. VI, p. 231, 1884; Expl. Albatross, Report U. S. Coin. Fish and Fisheries 

 for 1883, p. 576, 1885. SMITH, E. A., Report Voy. Challenger, Zool., Lamelli- 

 brauchiata. XIII, p. 248, 1885. DALL, Bull. U. S. Nat. Mus., No. 37, p. 46, 1889. 

 VERRILL and BUSH, Amer. Jonru. Sci., Ill, p. 53, figs. 1, 2, January, 1897. 



The specimens which we refer to this species agree closely in size and 

 form with Jeffreys's figures, but there is in both valves a small submar- 

 ginal lateral tooth just beyond the posterior series of teeth, and in the 

 right valve a similar but less prominent one just beyond the anterior 

 series. These are not mentioned in Jeffreys's description. In the pos- 

 terior series there are fewer teeth than in his figure and they have an 

 acute, oblique, V shaped outline and are but little raised; in the ante- 

 rior series there are four larger, oblique teeth which are not so dis- 

 tinctly V-shaped, owing to their oblique position and because the sur- 

 face of the hinge-plate is turned downward. The posterior ligament is 

 strong, long, wedge-shaped, widest distally where it occupies most of 

 the width of the hinge plate; the narrow prolongation runs forward 

 under the beaks in a narrow groove. There is a thickened, edentulous 

 space under the beaks, separating the two series of teeth, which has, 

 when highly magnified, a very small, angular notch in the middle of its 

 lower edge, which in our specimen is filled with what appears like the 

 remains of a resilium; there is also a very minute, V-shaped notch in 

 the external margin. The beaks turn forward. The pallial impres- 

 sion is rather indistinct, but appears entire. Interior somewhat lus- 

 trous, but not at all nacreous. 



Two imperfect specimens, at two stations, off Marthas Vineyard and 

 off Delaware Bay, in 1,544 and 1,608 fathoms, 1883 and 1886. South to 

 Rio de la Plata, in 294 to 1,900 fathoms. Dall and Smith. 



REVIEW OF THE GENERA OF LEDID^E AND NUCULID.E OF THE ATLAN- 

 TIC COAST OF THE UNITED STATES. 1 



These families are often united by modern inalacologists under a sin- 

 gle family (Xuculidai), while others regard them as distinct. They are 

 certainly closely related anatomically, as well as by the structure of the 

 shell. Thus all the members of both families have a single pair of 



1 An abstract of the portion of this article relating to these families was published 

 in the Americau Jourual of Science, III, p. 51, January, 1897. 



