290 BULLETIN OF THE 



Verticordia Seguenzae Dall. 



Shell having nearly the form of V. australiensis Smith (Chall. Lam., p. 167, 

 pi. XXV. figs. 6-6 b), with thin rather convex valves, greenish color, and about 

 forty radiating posteriorly convexly curved faint sulci, the interspaces between 

 which are gently rounded but little elevated, and hardly to be called ribs, and 

 have intercalary groovings toward the margin. The surface is covered with 

 minute glassy grains arranged with some regularity in radiating and concentric 

 series. As compared with V. australiensis the anterior dorsal margin is more 

 elevated and rounded up; the posterior margin is less curved. V. trapezoidea 

 Seguenza has the posterior dorsal margin much more curved, the anterior more 

 oblique, and the hinge is different, putting it in another section of the genus. 

 In V. SegxLenzcB the ossicle is very small, flatter than in the typical species, 

 rectangular, and wider behind; the length of the most perfect valve is 5.0, the 

 altitude 4.0, and the diameter, taken as twice that of the single valve, would 

 be 3.5 mm. A large dead valve, perhaps of this species, was found at Station 

 2602. 



Habitat. Yucatan Strait, 640 fms., one valve; U. S. Fish Commission, 

 thirty-six miles south of Cape Hatteras, at Station 2602, in 124 fms., and about 

 the same distance southeast of Cape Lookout, N(;rth Carolina, at Station 2614, 

 in 168 fms., bottom in both cases sand, and bottom temperature about 61° F, 

 (three valves). 



Although there is but little material, yet the species does not come very 

 close to any of those with which I could compare it, and it seemed worthy 

 of a name. The hinge, though delicate and with small teeth is that of the 

 typical Verticordia. 



Verticordia (Trigonulina) ornata D'Orbignt. 



Verhcm-dia ornata Dall, Bull. M. C. Z , IX. p. 105, 1881. 



Trigonulina ornata D'Orb., Moll. Cuba, II , p. 292, pi. xxvii. figs. 30-33, 1846. 



Verticordia ccelata Verrill, 1884 ; Trans. Conn. Acad., V. 566 ; VI., pi. xxx. figs. 9, 9 a. 



Habitat. Barbados, 100 fms. ; Station 19, 310 fms. (Catalina Island, Cal., 

 16 fms., Dall; Jamaica, W. I., D'Orb. ; China Seas, Adams ; east coast of the 

 United States off the Carolinas, and northward as far as Station 949, off Mar- 

 tha's Vinej'ard, in 100 fms., U. S. Fish Commission). 



The sculpture of this elegant species -is composed of curved ribs, radiating 

 from the umbones and crowded in front with two or more gaps behind. There 

 may be a posterior rib forming the extreme margin, or the hindermost rib may 

 be within the margin, two cases figured by D'Orbigny; or the posterior ribs 

 may fail altogether, forming the variety ccelata Verrill. The ribs may all or in 

 part be grouped in pairs, or the pairs may resemble a wide rib deeply grooved 

 along its summit. The ribs may be high and strong, or low and uniform ; in 



