MUSEUM OF COMPARATIVE ZOOLOGY. 115 



Corbula disparilis D'Orbignt, 

 C. disparilis B'Orhigny, S; gra, Moll. Cub., II. p. 283, Tab. XXVII. figs. 1-4, 1853. 



Off the west coast of Florida, in. 30 and 50 fms. (fine large specimens) ; 

 Station 12, 36 fms. ; off Sombrero, 72 fms. ; Station 36, 84 fms. ; Barbados, 

 100 fms. ; Sigsbee, off Havana, in 127 and 450 fms. ; Station 2, 805 fms. 



A well-marked species, with a wide range in depth, as the above record 

 indicates. 



Corbula cymella n. s. 



Shell of somewhat the general character of C. fragilis and C. scaphoides 

 (from the Pacific coast of Mexico and the Philippines respectively), but differ- 

 ing in proportions from either. Color whitish with a brownish tinge at the 

 margins, internally with a glassy poli.sh, externally duU ; shell inequilateral, 

 one third being anterior to the umbones ; inequivalve, but not markedly so ; 

 anterior margin evenly rounded ; ventral margin waved, slightly concave 

 nearly opposite the beaks, then swelling, then again a little concave just before 

 the posterior angulation ; posterior haemal margin straight, declining from the 

 beaks to the first angulation, then obliquely straightly truncated toward the 

 extremely acute posterior angle formed by the principal carina ; beaks moder- 

 ately prominent, flattened on top, not involute ; from them a strong rounded 

 carina extends to the tips of the shell, growing sharper posteriorly ; another 

 fine but very sharp carina extends from above tlie ligament close to and nearly 

 parallel with the hinge margin, which it.s posterior termination slightly angu- 

 lates ; these form an extremely narrow concave lunule, while the space be- 

 tween these carinas and the more prominent second pair of carinse is distinctly 

 excavated, and is crossed by the wave-like sculpture only near the posterior 

 portion, the rest being nearly smooth, except for the extremely fine radiating 

 lines, which are better defined here than elsewhere on the shell ; these last 

 cover the entire shell, and have not the appearance of grooves, they are vis- 

 ible only with a glass, and are best defined on the posterior face, as above men- 

 tioned, and in the furrows; other sculpture of about ten regular concentric 

 waves, with wider and very uniform interspaces, which, however, in adults (as 

 in all Corbula;) begin to be crowded at the extreme margin ; there is no ante- 

 rior lunule or carina, the tooth is very slender and small, and the whole shell 

 is very thin. Lon. 13.5 ; alt. at beaks, 7.5 ; max. diameter, 5.0 mm. 



Gordon Key, in 68 fms. 



This species is remarkable for its aci;niinated posterior end, and as very thin, 

 nearly equivalve, ventrally slightly concave, and for its slender and elongated 

 form. 



