MUSEUM OF COMPAKATIVE ZOOLOGY. 291 



the latter case they are usually more numerous ; the number of ribs may be 

 from eight to twelve ; I have not in over one hundred and fifty valves found 

 more or fewer. The interspaces may be irregularly granulose or finely radi- 

 ately striate. The degree of compression varies somewhat, and the posterior 

 end may be more or less angulated below. The extremes seem very unlike, 

 but are perfectly connected by intermediate specimens. The average specimen 

 has six to eight anterior ribs, a gap, one or two ribs, a wider gap, and one or 

 two more ribs near or at the posterior margin. The commonest form has 

 A 6, 0, 1, 0, 1 P, for its rib formula. 



Verticordia (Euciroa) elegantissima Dall. 



Verticordia elegantissima Dall, Bull. M. C. Z., IX. p. 106, 1881. 

 Plate II. Figs. 1 a, 1 b. 



Habitat. Station 16, 292 fms. (fragments), oflf Havana, Cuba, and Station 

 18, in Lat. 23° 7' and Lon. 82° 43' 30" W., oflf Muriel, Cuba, 756 fms. (a single 

 valve) ; bottom temperature 55^.7 and 40°. F. respectively. 



A little more material in regard to this large and elegant species has come to 

 hand. The perfect valve represented in the figure was carelessly cracked by 

 the artist under the object-glass of his instrument. It has been tolerably re- 

 paired, but fresh and perfect specimens ought to be found by somebody. The 

 Fish Commission has dredged some imperfect valves (winter of 1885-86) at 

 Stations 2659 and 2660, off Cape Canaveral, in 509 and 504 fms., bottom tem- 

 perature 45°. 2 and 45°.7 F. respectively. The best of these is 40.0 long, 38.0 

 high, and -3^- mm. in diameter, showing a more rounded form than in the young 

 valve figured, and being the largest known species of the family. The interior 

 is strongly radiately striate toward the pallial line, and the scar of the pedal 

 muscle strongly marked. 



Verticordia (Haliris) Fischeriana Dall. 



Verticordia Fischeriana Dall, Bull. M. C. Z., IX. p. 106, 1881. 

 Plate II. Figs. 4 a, 4 b. 



Habitat. Barbados, 100 fms.; Sigsbee, off Cuba, 119 fms.; and, living, at 

 Station 36, Lat. 23° 13' N., Lon. 89° 16' W. Gr., in the Gulf of Mexico, in 

 84 fms., bottom temperature 60°. F. A single valve was dredged off Rinal- 

 do's Chair in 160 fms. by the Porcupine expedition, 1870, and was found 

 mixed with specimens of V. trapezoidea Seg., in the Jeffreys collection. It 

 has also been dredged by the U. S. Fish Commission at Stations 2600, 2601, 

 and 2602, in 87-124 fms., about thirty-six miles off Cape Hutteras. 



The ribs of this species vary in sharpness, and when very sharp are serrate 

 by the granulations which on the keel of the ribs become more prominent than 



