V<ll 



Vga"'] PROCEEDINGS OF THE NATIONAL MUSEUM. 253 



the umbo; the concentric ridges are about equal to their interspaces; 

 tbere is a pale yellow concentrically finely wrinkled epidermis ; tbe 

 tips of tbe umbones are full, smootb, and polished; there is a lanceolate, 

 smoothish lunule bounded by an obscure ridge, and a shorter and nar- 

 rower escutcheon bounded by a faint ridge, outside of which is a faint 

 depression ; on either side of the beaks is a narrow, flattened area, 

 recalling that of Limopsis, but much smaller and narrower; in the middle 

 of this, just under the beaks, is a very small socket for the ligament, 

 which is wholly external to the line of the teeth, just as in Palceoneilo; 

 there are eleven developed and three obsolete anterior teeth and about 

 twelve posterior teeth, of which two or three are very small; the two 

 sets are separated by a very narrow, smooth space, but there is no car- 

 tilage; the muscular scars are deep, the pallial line obscure, the margin 

 simple, and the valves rather thick; maximum longitude of shell 5.5; 

 maximum altitude 4.5; diameter 3.1 n,m ; the beaks are over a point on 

 the line of maximum length, which is 3.25 mm fr6m the anterior end. 



Hab. — Station 2751, south from St. Kitts, in 687 fathoms ; and 2754, 

 east from Tobago, in 880 fathoms; temperatures 37°.9 to 39°.9 F. 



This species has much the outline of Modiolarca exilis H. and A. 

 Adams (see Zool. Kergueleu Id., Mollusca, by E. A. Smith, Transit of 

 Venus Expedition, Zool., Plate ix, Fig. 24), and resembles in stoutness 

 and sculpture Leda Brookei Hanley, as figured in the Thesaurus. 



Malletia (Tindaria) acinula sp. nov. 

 Plate XIII, Fig. 4. 



Shell small, subquadrangular, white, with the anterior end shortest, 

 and the surface sculptured with strong, close, subequal, rounded con- 

 centric waves, separated by linear interspaces ; base produced in the 

 middle, rounded; anterior end short, rounded; posterior end longer, 

 with a rounded point, but not rostrate; beaks apical, but not prominent; 

 lunule and escutcheon subequal, small, narrow, impressed, rather short, 

 with no bounding elevated line or groove; ligament small, longer than 

 high, directly under the beaks, external to the tooth line, and visible 

 externally in the closed shell; anterior part of the hinge with eight, 

 posterior part with ten, V-shaped teeth, of which two or three on each 

 side are very small; scars well marked, impressed; pallial line obscure, 

 arcuated in front of the posterior adductor; margin of the valves plain, 

 interior polished, shell rather thick; maximum longitude of shell 5.0; 

 maximum altitude, 4.2; diameter 3.5; distance of vertical, drawn from 

 the beaks, from anterior end, 1.5 mm . 



Hab. — With the last and also at Station 2760, in 1,019 fathoms, brown 

 clay, ninety miles north from Ceara, Brazil; temperature 39°. 4 F. 



This shell has much the outline of Leda quadrangularis Dall, but is 

 proportionally higher and shorter, with more prominent and regular 

 concentric sculpture, 



