46 2 MAZATLAN UNIVALVES 
minent and two less prominent folds, and sometimes a fifth 
slightly developed. Labrum smooth. The spire, which is 
shghtly elevated, has its whirls concealed by the parietal callus, 
but there are either 4 or5 in the adult. The youngest sp. 
measures ‘025, by 016; the largest adult, Zong. °085, long. 
spir. 015, lat. °054, div. 120°. 
Hab.—Panama, 10 sp. C. B. Adams —Mazatlan ; not uncom- 
mon on Chama, Spondylus, and Modiola capax ; L’pool Col. 
Tablet 2107 contains 7 young, and 3 adult sp., varying in 
outline. 
588. MARGINELLA POLITA, 7. S. 
M, t. “M. minore” simili; sed minore, regulariter ovatd, 
antice vix productid, spiré rotundatda, haud extante ; callo parie- 
talt minore: plicis iv. subequalihus, conspicuis. 
This species is regularly elliptical, with the foci near. The 
specimens found may not be mature, though they appear 
normally formed. They do not accord with the yeung of the 
last species, which, though it varies somewhat, gives no signs 
of assuming the form of this. The shell is extremely glossy. 
Long. °034, long. spir. °002, lat. ‘022, div. 150°. 
Hab.—Mazatlan; 6 sp. off Chama and Spondylus ; L’pool Col. 
Tablet 2108 contains the smallest and largest sp. and one 
somewhat aberrant. 
589. MARGINELLA MARGARITULA, 2%. S. 
M. t. parva, ahd, polita; interdum striulis incrementi haud 
conspicuis ; ovatd, antice et postice haud angusta ; spird, t. gunt- 
ore et adultd, omnino celaté ; apertura elongata, angustd, spire 
superante ; labro t.juniore acuto, adultd ut in Cypred incur- 
vato, dentato ; postice canaliculato, callositate parietali munito ; 
plicis iv. distinctis, posticis in adulté undatis, basalibus majort- 
bus ; interdum denticulis parietalibus minimis ; labio parietalt 
nullo. 
Comp. Marginella ovuliformis, D’ Orb. B. M. Cat. Cub. Moll. 
p. 24, no. 281. 
This little species partakes of the characters of Persicula, 
and is extremely like the W. Indian P. clandestina: from 
which it differs (if rightly placed by Messrs. Adams among 
