302 REPORT OF NATIONAL MUSEUM, 1897. 



VERTEBRALINA INSIGNIS Brady. 

 (Plate 47, fig. 4.) 



Much compressed, nearly symmetrical bilaterally, margin angular, 

 often keeled. Early segments may be planospiral (in one specimen this 

 arrangement of the minute early chambers is quite evident), or milioline, 

 or both; latest segments united at such an angle that the last three 

 include all the others; no chambers of the straight series appear in the 

 specimens shown. Surface rather coarsely striate; aperture a long 

 oval mouth with everted lips. 



Localities. — Gulf of Mexico, coast of Florida, and off Chesapeake 

 Bay (stations 2400, 2420, 2641), 60 to 169 fathoms. 



Genus OPHTHALMIDIUM. 



Cornuspira-like at the commencement, subsequently with two or more 

 segments in each convolution. 



OPHTHALMIDIUM INCONSTANS Brady. 

 (Plate 47, fig. 3.) 



A thin, flat shell; begins with a small central globular chamber ; con- 

 tinues as a fine, coiled, non-septate tube, and ends by tbe tube becoming 

 larger and divided into chambers by constriction at opposite points in 

 each convolution. Segments with broad keels which separate the con- 

 volutions. 



Localities. — Gulf of Mexico, Bahama Islands, coast of North Carolina 

 (stations 2392, 2629, 2614), 168 to 1,169 fathoms. 



Genus PLANISPIRINA. 



Chambers milioline at tbe commencement, subsequently planospiral; 

 the lateral alar prolongations of the latest convolution inclosing the 

 previous whorls. 



PLANISPIRINA SIGMOIDEA Brady. 

 (Plate 47, fig. 6.) 



Compressed, nearly circular, projecting slightly at the ends, the two 

 faces unequally convex, and the margin thin but rounded; segments 

 two to each convolution, and set on at the margin of alternate sides, 

 producing a milioline arrangement of the chambers; surface smooth 

 and shining; aperture a gaping, transverse orifice in the oral promi- 

 nence. Diameter, about 0.75 mm. (^ inch). Transverse section shows 

 arrangement of the chambers, and, indistinctly, the successive layers 

 of which the sides of the shell are composed. 



Localities. — West India Islands, Bahamas, Trinidad, and coast of 

 Brazil (stations 2117, 2629, 2754, 2760), 680 to 1,170 fathoms. 



