462 MAZATLAN UNIVALVES 



minent aud two less promiuent folds, and sometimes a fifth 

 slightly developed. Labnim smooth. The spire, which is 

 slightly elevated, has its whirls concealed by the parietal callus, 

 but there are either 4 or 5 in the adult. The youngest sp. 

 measures •025, by -016; the largest adult, long. '085, lojig. 

 spir. -015, lat. '054, div. 120°. 



Sab. — Panama, 10 sp. C. B. Adams. — Mazatlan ; not uncom- 

 mon on Chama, SpOndylus, and ]\Iodiola capax ; L'pool Col. 



Tablet 2107 contains 7 young, and 3 adult sp., varying in 

 outline. 



588. Marginella polita, n. s. 



Jif. t. " M. ininore" simili ; sed minore, regulariter ovatd, 

 antice vix productd, spird rotundatd, haud extante ; callo parie- 

 tali minore : plicis iv. suba'qualibns, conspicuis. 



This species is regularly elliptical, with the foci near. The 

 specimens found may not be matxire, though they appear 

 normally formed. They do not accord with the young of the 

 last species, which, though it varies somewhat, gives no signs 

 of assimiing the form of this. The shell is extremelj' glossy. 

 Long. -031, long. spir. "002, lat. '022, div. 150". 



I£ab. — Mazatlan ; 6 sp. off Chama and Spondylus ; L'pool Col. 



Tablet 2108 contains the smallest and largest sp. aud one 

 somewhat aberrant. 



589. Maeginella maegaeitula, n. s. 



M. t. parvd, alba, politd ; interdum striulis incrementi haud 

 conspicuis ; ovatd, antice et post ice haicd angustd ; spird, t.juni- 

 ore et adultd, onmino celatd ; aperiurd elongatd, angustd, spircB 

 .niperajtte ; labro t.juniore acuto, adultd ut in Ci/prced incur- 

 vato, dentato ; posiice canaliculaio, callositate parietali munito ; 

 plicis iv. distinetis, posticis in adultd undatis, basalibvs majori- 

 bus ; interdum deiiticulis parietalibus minimis; labia parietali 

 nulla. 



Comp. Marginclla oviJiformis, D'Orb. B. M. Cat. Cub. Moll. 



p. 21, no. 281. 



This little species partakes of the characters of Persicula, 

 and is extremely like the W. Indian P. claudestina : from 

 which it differs (if rightly placed by Messrs. Adams among 



