MUSEUM OF COMPARATIVE 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 
A6, 0, 1, 0, 1 P, for its rib formula. 
Verticordia (Euciroa) elegantissima Datt. 
Verticordia elegantissima Dall, Bull. M. C. Z., IX. p. 106, 1881. 
Plate II. Figs. la, 1 b. 
Habitat. Station 16, 292 fms. (fragments), off Havana, Cuba, and Station 
18, in Lat. 23° 7’ and Lon. 82° 43’ 30" W., off Muriel, Cuba, 756 fms. (a single 
valve); bottom temperature 55°.7 and 40°.0 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 43 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 Datt. 
Verticordia Fischeriana Dall, Bull. M. C. Z., IX. p. 106, 1881. 
Plate Il. Figs. 4a, 4b. 
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°.0 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 Hatteras. 
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 
