378 Trans. Acad. Sci. of St. Louis. 



MUREX NIGRESCENS Sowb. 



Murex nigrescens Sowb., Conch. 111., fig. 113. 



From a careful study of numerous material I am led to con- 

 clude that this species is specifically distinct from messorius. 

 The canal is considerably curved, the spire is long and coni- 

 cal, and the shell is almost destitute of spines, some specimens 

 possessing but a single spine on the canal just below the 

 aperture. The varices are thick and strong, and the spiral 

 lines well developed. The general color of the shell is ashy 

 with a dark brown band above the periphery of the body- 

 whorl. The species is confined to the Panamic province. 



Murex rectirostris Sowb. 



Murex rectirostris Sowb, Proc. Zool. Soc, 1840. Conch. 111., fig. 111. 



I know of no good description of this beautiful species, and 

 the one which follows, and which was drawn from over a 

 dozen fine specimens, seems quite necessary. 



Shell fusiform, whitish, with two broad brown spiral 

 bands; sutures deeply impressed; whorls 8^, the two apical 

 smooth and glossy, the second provided with a well-marked 

 carnia near the suture of the third whorl; the rest of the 

 whorls rounded, somewhat shouldered at the suture, trivari- 

 cose, with three nodules between the varices; the latter are 

 provided with one strong spine at the suture of the whorls ; 

 whorls ornamented by fine spiral lines, which rise into ridges 

 on the varices and nodules; spire high, about twice the 

 length of the aperture ; canal long, straight and about three 

 times the length of the aperture and crossed by from 16 to 20 

 coarse lirae ; a short spine is frequently developed to the left 

 of the inner lip ; aperture ovate, white ; outer lip thin at the 

 edge and denticulated ; inner lip erect, thin and raised over 

 the columella, at the lower end of which it runs into the long, 

 closed canal. Alt., 70; diam., 25 ; aperture alt., 13; diam., 

 9 mill. Canal 40 mill. long. 



Habitat. Xipixapi, West Columbia, in 11 fathoms (Cum- 

 ing); China (Sowerby). 



This species is separated from recurvirostris, Sowb., by the 

 greater elevation of the spire, comparatively longer canal and 

 the entire absence of any indication of an old snout end ; and 



