30 THE NAUTILI'S. 



u fiin-uw ill its place, bounded by a fosciole ; aperture purple with- 

 in ; apex minute, knob-shaped, smooth. 



Alt. 32, diain. 15 millimeters. Aperture (including canal) alt. 6, 

 diam. 6 millimeters. 



It is separated from cinereus by its greater proportional width, its 

 stronger ribs and spiral Yirx and more scabrous texture. It is at 

 once separated from tmnpaensls by the sculpture; that of tampaen- 

 sis being latticed by the intersection of the longitudinal and spiral 

 lines; there are other differences which will at once distinguish it 

 from that species. 



Specimens have been collected at Cedar Keys, by j\Ir. Henry 

 Hemphill, and I understand from collectors that it has been found 

 elsewhere on the west coast of Florida. 



PRESERVATION OF COLOR IN FOSSIL SHELLS. 



BY CHARLES R. KEYES. 



Recently some interesting fossils have come under my notice : Tra- 

 chydomia xvheeleri Swallow from the Coal Measures of Illinois. The 

 group is a member of the Njiticidie, a family which in the American 

 Paliieozoic is also represented by several other genera. The shells 

 alluded to, while Natica-like in general aspect, are rather small in 

 size, massive, with the surface covered with numerous conspicuous 

 nodes, and the callosity of the inner lip greatly thickened and ex- 

 tended. Among the specimens are a number in which the coloration 

 of the callous portions and of the interior surface is still visible. In 

 some individuals the color is an intense shining black ; iu some a 

 purplish-black ; in others dull fiided purple ; and in a few the color 

 has entirely disappeared. Aside from the apertural parts all traces 

 of the original coloration of the shell are lost. Apropos it may be 

 mentioned that de Koninck has also called attention to examples of 

 Macrochllus from the Carbonic of Belgium, having the maculate sur- 

 face still apparent. The markings in this instance consist of series 

 of large rectangular spots. And it is presumable that the shells of 

 this Carbonic group were originally brightly colored and presented 

 an appearance similar to many recent forms of the genera Mitra and 

 Conus. In the Loss (post-pleiocene) deposits of the Upper Missis- 

 sippi Valley there are some forty or more species of land and fluvia- 

 tile shells known ; the majority of which are still found living with- 



