I 



MAZATLAN UNIVALVES 387 



portion wliicli probablj^ belongs to this species, thottgli it ap- 

 pears more slender. Long. 1'22, long. spir. '96, lat. •25, div. 13°. 

 jffai.— Mazatlau ; extremely rare ; L'pool Col. 

 Tablet 1838 contains the shell and the spiral fragment. 



Gentts STJBULA, Schum. 



Subula, Schum. Ess. 1817, pars.— Distinguished by haying the 

 eyes on the tips of the tentacles, instead of on their outer 

 bases ; in the shell, by the absence of the spii-al band, 

 sinuated lip and canal. 



Acus (Humph.) Gray, 1847, Proc. Zool. Soc. 1847, p. 139.— 

 S. Sf A. Ad. Gen. vol. i. p. 224.— Comp. Gray, Gen. Moll. 1856. 



Terebra (pars) auct. 



'454. Stjbula ltjcttjosa. Hinds. 



Terebra luctuosa, Proc. Zool. Soc. 1843, ^.lol.— Hinds in Sow. 

 TJics. Conch, p. 181, no. 89, pi. 45, f. 121 .—Menhe in Zeit. 

 f. Mai. 1851, p. 34, no. 119. 

 Hastula (Acus) luctuosa, H. ^^ A. Ad. Gen. i. 225. 



Shell nearly related to S. cinerea and S. strigilata from 

 the E. Indies. Lustrous, with extremely fine, crowded spiral 

 stripe, generally consisting of minute dots ; and very numerous, 

 fine, slightly waved, sharp ribs on the upper part of the whirls, 

 evanescent in the middle. Between these are often extremely 

 minute radiating striulte. About 6 of the first whirls are 

 translucent and without ribs. Apex submamillary. First 

 normal whirls with ribs strong. Outline very acuminate and 

 nearly rectilinear. The outer lip when perfect, wliich it rarely 

 is, is gracefully sinuated posteriorly in the direction of the 

 ribs. About half the specimens are of an ashy or olivaceous 

 brown ; the remainder of a lustrous brown black, often fading 

 into light blue ; with scarcely any intermediate shades. Highly 

 coloured specimens are sometimes found of a very dark olive 

 green, with a row of infrasutural spots of purplish brown, 

 sometimes over a yellowish green ground, occasionally con- 

 fluent. The operciilum is small, thin, horny, ovate, with faint 

 waves of growth : its apex is terminal. The largest of the speci- 

 mens, (making allowance for the tip which is broken off,) 

 measures long. 1'84, long. spir. 1'4, lat. '33, div. 12". 



A broad sp. „ 1'62, „ 1'18, „ "34, „ 14°. 



An attenuated sp. „ 1'37, „ 103,,, '26, „ 11°. 



