318 REPORT OF NATIONAL MUSEUM, 1897. 



CRISTELLARIA CULTRATA Montfort. 

 (Plate 65, fig. 2.) 



A lenticular, biconvex, smooth shell, in all general characters like 

 C. rotulata except the peripheral margin, which in this species is 

 extended into a thin, broad wing or keel. Diameter, 2 mm. (^ inch), 

 more or less. 



Locality.— Gulf of Mexico (stations 2399, 2400), 196 and 169 fathoms. 



CRISTELLARIA CALCAR Linnaeus. 

 (Plate 66, fig. 1.) 



Lenticular, biconvex, smooth, carinate, in some instances with a broad 

 keel notched and spinous at the edge, in other cases with a narrow 

 keel and long, slender, radiating spines. Size variable ; the large 

 specimens generally have the broad keel and the small ones the long 

 spines. 



Localities. — Off the coast of the Carolinas and in the Gulf of Mexico 

 (stations 2312, 2313, 2679, 2377, 2100), 88 to 782 fathoms. 



CRISTELLARIA ECHINATA d'Orbigny. 

 (Plate 66, fig. 2.) 



Test lenticular; margin either rounded or keeled and projected into 

 more or less numerous radiating processes ; sutures limbate and beaded. 

 Diameter, 1.25 to 2.50 mm. (-^ to ■£$ inch). 



Locality.— Gulf of Mexico (stations 2377, 2399, 2400), 169 to 210 

 fathoms. 



CRISTELLARIA ACULEATA d'Orbigny. 

 (Plate 66, fig. 3.) 



Elongate, moderately compressed ; early segments planospiral, later 

 ones rectilinear or curved; sutures oblique and conspicuously marked 

 by rounded tubercles or short, stout spines; general surface, especially 

 of the earlier segments, often tuberculated or spinous, peripheral edge 

 sometimes finished with several long, slender spines. 



Locality.— Gulf of Mexico (stations 2377, 2399), 210 and 196 fathoms. 



CRISTELLARIA LIMBATA, new species. 

 (Plate 67, fig. 1.) 



Elongate, evolute, slightly compressed, resembling C. aculeata in 

 contour and arrangement of the segments; peripheral margin more or 

 less spinous; sutures covered by thick, smooth, prominent bands of 

 transparent shell substance, without tubercles or spines. Length, 

 about 2 mm. d 1 ., inch). 



Locality.— Gulf of Mexico (stations 2377, 2399), 210 and 196 fathoms. 



