164 BULLETIN OF THE 



rather well marked ; spiral sculpture of rather strong threads, strongest on the 

 anterior part of the whorl and obsolete behind the periphery ; aperture nar- 

 row, outer lip thickish, not reflected, smooth inside; body whorl free from 

 callus ; columella with four strong subequal plaits and one or two obscure 

 anterior folds ; color whitish or brownish when faded, plum color and white 

 variegated when fresh. Lon. (of two specimens) of shell, 10.0 and 8.0; of 

 aperture, 6.25 and 5.50; max. lat. of shell, 5.0 and 4.6 mm. 



Habitat. Yucatan Strait, 640 fms., two dead specimens. 



This form is related to Gonomitra minima Seguenza, Form. Terz. Reggio, 

 p. 101, pi. xi. fig. 4, 1879, but is about twice as large. The latter is from the 

 Tortonian division of the Sicilian Miocene. 



Conoraitra Blakeana var. laevior. 



Plate XXXV. Fig. 10. 



Shell resembling the preceding in form and size, but smooth or with but 

 few faint plaits on the apical whorls; color orange, or flaked and clouded with 

 opaque white, or marbled like Meta cedonulli; the spiral threads are absent 

 except a few on the canal; the whorls are more appressed and the appearance 

 of the spire less stumpy. Lon. of shell, 9.75 ; max. lat. 4.6 mm. 



Habitat. Stations 57, in 177 fms., and 62, in 80 fms., off Havana; dredged 

 by Sigsbee while in search of Pentacrinus. Also in 300 fms., mud, off Cape 

 San Antonio, by Dr. Rush. 



This must be a charming shell when in good order, and apparently must 

 inhabit moderate depths of water. 



Genus MITROMORPHA Adams. 



Mitromorpha A. Adams (Cpr.), Ann. Mag. Nat. Hist., 3d ser., XV. p. 182, March, 

 1865. {M.Jilosa Cpr.) 



This group, though indicated, seems not to have been characterized by either 

 Adams or Carpenter, and it may be well to indicate its chief features. The 

 form of the typical species is biconic with a globose nucleus, a narrow aperture 

 very slightly or not at all notched behind, a nearly straight columella on 

 which (1) the spiral riblets of the sculpture may run into the interior; or 

 (2) may be overlaid with a smooth layer of callus ; or (3), while in either con- 

 dition, may have two faint oblique ridges on the column, which, however, are 

 not continuous within the shell. The outer lip is thickened, but not reflected, 

 and lirate or denticulate a little way within the margin. The nucleus is like 

 that of some of the small Mitras, the shell (as in M. dormitor Sby.) recalls 

 Columhella, Conus, Cithara, etc. The spiral sculpture is usually stronger than 

 the transverse. My own impression, subject to modification with greater 

 knowledge, is that these shells are related to MUra rather than Daphnella, etc. 



