80 OLIVA. 



Yar. TREMULINA, Lam. Figs. 46-52. 



This shows the same range of variation in color as the typical 

 irisans, and only differs in its greater size and solidity. 



Length, 3'5-4 inches. 



The synonyms are 0. nobilis, Reeve (fig. 48), 0. tenebrosa, 

 Marr. (fig. 49), O.fumosa, Marr. (fig. 50), and 0. olympiad ina, 

 Duclos = 0. pica, Lam. (figs. 51, 52). 



Yar. ERYTHROSTOMA, Lam. PI. 1, fig. 3 ; PL 26, figs. 53, 54 ; PL 

 27, figs. 55-58; PL 34, fig. 53. 



Shell cream- or flesh-color, with violet or red zigzag longitu- 

 dinal lines, which are A r ery irregular and rather distant, and 

 frequently shaded with orange ; there are two bluish violet 

 interrupted bands ; interior of aperture bright orange-red. 



Length, 2-3 inches. 



Ordinarily the coloring of this form is sufficiently distinctive, 

 so that I hesitated whether to give it specific or varietal rank ; 

 I am induced to favor the latter because a number of specimens 

 are before me which are intermediate between this and the last 

 variety : thus, some have the external coloration of erythrostoma, 

 more or less, with the aperture white within, others are colored 

 like tremulina (some of them uniform dark chocolate), with the 

 aperture varying from the faintest blush to deep orange-red. 



The sj'iionyms are 0. magnifica, Ducros = 0. tremulina (in 

 part^, Marrat (fig. 54), 0. azemula, Duclos (fig. 55), 0. mazaris, 

 Duclos (fig. 56), 0. sylvia, Duclos (figs. 57, 58), and 0. ponderosa, 

 Duclos (PL 34, fig. 53), a thick-growing form. 



Yar. TEXTILINA, Lam. PL 27, figs. 59, 60. 



Cream-colored, very light yellowish or pink, closely reticulated 

 by zigzag chestnut markings, usually forming a superior and a 

 median band of darker reticulations ; aperture white or light 

 flesh-color. Length, 2-3 inches. 



This is also typically a very distinct shell, in its close 

 reticulated pattern and in the bands being formed of darker 

 reticulations and not of markings confluent into blotches ; yet 

 in some specimens these blotches appear, and in others they 

 spread more and more so as to form a complete series from the 

 type to the uniformly chocolate-colored shell ; on the other hand. 



