MUSEUM OF COMPARATIVE ZOOLOGY. 125 



beaks, the anterior end is more pointed, and the basal margin, instead of being 

 rather evenly arcuated, is particularly produced in the middle just behind the 

 vertical line of the beaks. It has six teeth before and eight behind the beaks, 

 and is about five millimeters in length. It does not exactly agree with any of 

 the figured species, recent or fossil, and is most like Philippi's figure of Nucula 

 glabra, if the relations of the parts were exactly reversed, anterior for posterior, 

 etc. It may take the varietal name of quadrangularis until more material 

 comes to hand, and may eventually prove to belong where I provisionally place 

 it, among the varieties of L. Jeffreysi. 



Leda dilatata Philippi. 



Nucula dilatata Phil., En. Moll. Sic, II. p. 47, Tab. XV. fig. 7, 1844. 

 Ncilo dilatata Seguenza, Nuc. terz., p. 1184, 1877. 



Off Morro Light in 292 fms. 



This shell agrees exactly with Philippi's figure and description, but it is not 

 a Neilo, the ligament being as usual in Leda and Yoldia. 



Leda Carpenteri n. s. 



Shell resembling in outline and size Leda hamata Carpenter, as figured by 

 Reeve in the Iconica (PI. IX. fig. 56), but with the rostrum less recurved. It 

 differs from that species in being thinner, anteriorly more pointed, in wanting 

 the strong epidermis, concentric ridges, and sharp rostral carinse. It is nearly 

 smooth, except for lines of growth, with a thin greenish polished epidermis ; a 

 ridge bounding the escutcheon proceeds from the inconspicuous beaks to the 

 dorsal angle of the rostrum ; the umbones hardly rise above the dorsal margin, 

 which pouts before and behind them, but hardly gapes ; an internal ridge 

 passes from the tip of the rostrum well into the umbonal cavity in most speci- 

 mens. Teeth, anterior 8-16, posterior 20-25. Lon. 10.5 ; alt. 5.0 ; diam. 

 2.5. mm. 



Barbados, 100 fms. ; Station 21, 287 fms. ; Station 5, 229 fms. ; Station 9, 

 111 fms. 



I have not been able to compare a figure of L. clavata Calcara, which is an 

 Italian fossil, apparently of somewhat this shape. A long search has not re- 

 vealed a figure or description of any recent species applicable to the form before 

 me, whose smoothness is remarkable. 



Leda (Neilonella) corpulenta n. s. 



Shell nearest to L. c(£lata Hinds, which is more deeply concentrically sul- 

 cated, with the rostral area smooth, or with a smooth bounding ridge, while in 

 L. corpulenta the strise and intervening finer ridges are carried clear over the 

 shell to the dorsal margin. The present species is more inflated, with a more 

 convex basal margin, with the beaks a little more anterior, both ends more 



