MUNdUKKOS. iy3 



(ienus MONOCEROS, l-ain 



This sinnll gr(ni|) is I'estricled in distrihution to the Pacific 

 coasts of North and South America and the neiahltoring islands. 

 It is also represented in the tertiary of Chili. 



M. GRANDE, Gray. PI. OO. tigs. 2s,S, 285-2.ST. 



Brown externally, ttesh-color within the apertnre. 

 Length. 2-5-3-5 inches. 



(Tdlhtpagos Islands. 



The young shell has the libs rounded, and not crossed by 

 scales. I have before me an extreme variety in which the s|nre 

 and canal are both produced an(J the ribs smooth. 



Length, 3'5 inches. 



M. MURicATUM, Brod. PI. CO, figs. 290, 2S'.). 



Yellowish or brownish ; aperture white or fiesh-color, the 

 revolving raised lines usually darker. Length, 2-5-;) inches. 



Piiinima to Mdzathnt. 



Varies greatly in appearance ; the typical foi-m having a ver^' 

 much depressed spire and broad shoulder on the body, the whole 

 surface very scabrous, whilst an extreme variety, described by 

 Gray as M. tuherculotum (fig. 289). has more elevated spire, the 

 surface not so scabrous, the ribs broken up into tubercles. 

 Carpenter, in his " Mazatlan Catalogue," refers this species to 

 Puj-pura, on account of the slight development of the horn in 

 the specimens which he studied ; R. E. C. Stearns (Am. Jour. 

 Conch., vii, 1*70) facetiously remarks that this horn is sufficiently 

 prominent in his specimens " to enable the shell to enter the 

 genus Monoceros on its own hook." This I can confirm. 



M. LUGUBRE, Sowb. PL 60, fig. 29L 



Yellowish brown, blotched or flamed with chocolate ; yellowish 

 brown within the movith. Length, 1-2 inches. 



Pacific and Oulf Coasts of Lower California. 



Sowei'by's is not the earliest published name for this species, 

 but it is so well known that it had better not be changed. 



