A. E. Verrill — Study of the family Pectinidcje. 85 



lines, crossing the stronger and more elevated concentric lines, but 

 not rising into points. 



The posterior dorsal area, below the auricle, is nearly smooth, 

 except for the fine lines of growth, but sometimes shows minute 

 granules. The right valve, which is smaller than the left, is covered 

 by fine, thin, close, concentric raised lines, which sometimes show 

 microscopic striations. 



The anterior auricle is decussated by six to eight or more, small 

 radial ridges, which are crossed by the raised concentric lines ; the 

 latter rise into sharp scales at the dorsal margin ; the small posterior 

 auricle has fine concentric lines and only two or three faint radial 

 ridges. 



Off the eastern coast of the United States ; 121 to 312 fath. 



The figures of this and various other species were forwarded, sev- 

 eral months ago, to the U. S. National Museum, to illustrate an arti- 

 cle in its Proceedings. 



Cyclopecten leptaleus Verrill. 



Pecten leptaleus Verrill, Trans. Conn. Acad., vol. vi, p.. 232, 1884; Bxpl. by the 

 Albatross, p. 577 [75], 1855. 



Dr. Dall has expressed a doubt as to whether this species is distinct 

 from P. imbrifer. In addition to the original description, it should 

 be stated that the concentric lines are somewhat thickened and 

 elevated, even where thinnest, and that the beaded character is quite 

 imlike anything found in P. imbrifer or allied species. The beads 

 are closely arranged, elliptical in form, and most elevated at the 

 center, the elevation being often greater than the diameter ; their 

 summits are smooth or glossy, so that when viewed from above, 

 under a lens, each often appears to have a central cavity. The 

 radial lines are comparatively very thin and delicate and not visible 

 except when considerably magnified. The beaks are more acute 

 than in P. imbrifer, and the nucleus is smaller and smoother. 



Off the eastern coast of the U. States ; in 142 fathoms off Cape 

 Hatteras. . 



Cyclopecten nanus Verrill and Bush, sp. nov.^ 



Plate XVI. figs. 12-12c. 



Shell small, the breadth and height about equal ; the valves are 

 nearly equal in size and convexity. Dorsal hinge-margin rather long 



^ Described and figured in an unpublished paper sent to Proc. U. S. Nat. Mus. 



