THE NAUTILUS. ( 
base; growth-lines fine and slight. ' Light flesh colored. Whorls 
about 64, the first globose, the second and third with rather coarse 
longitudinal folds, which persist longer at the upper part of the whorl ; 
remaining whorls convex, foldless ; the last whorl oval, regularly con- 
vex, contracted below, with a wide arcuately striate siphonal fas- 
ciole bounded above by a strong narrow spiral rib. Aperture a lit- 
tle over half the alt. of shell. Columella broadly concave above, 
having a strongly twisted fold below, which projects at the junction 
of the short basal canal with the cavity of the aperture, sloping 
strongly to the left below the projecting fold; anterior notch wide. 
Parietal callus rather thin, spreading far forward. 
Length 22°5, diam. 12 mm. 
Maldonado Bay. This species is certainly not the young of B. 
cochlidium, although in my opinion d@’Orbigny’s fig. 25 of plate 61 
of the Voy. Am. Mérid. was drawn from a specimen of the form here 
described. The characters of columella and sculpture also incline 
me to consider the present species distinct from B. Lamarck 
Kiener (Iconogr., pl. 3, figs. 6, 6). 
Chlorostoma (Omphalius) corrugatum Koch. Trochus patagoni- 
cus Orb. is'a synonym. 
Columbella avara Say. 
Columbella obesa var. decipiens C. B. Ad. 
Columbella sertulariarum d’Orb. 
Crepidula aculeata Gmel. 
Cylichnella bidentata Orb. 
Fissuridea patagonica d’Orb. 
Halistylus columna Dall. 
Halistylus cireumstriatus n. sp. Similar to H. columna in size and 
contour, but the whorls are encircled by numerous impressed brown 
lines. H. pupoideus (Cpr.) Dall, of California, (Proc. U. S. Nat. 
Mus., xv, 1892, pl. 19, f. 2) is a third species of this interesting 
group. It is spirally sculptured like cirewmstriatus, but has very 
convex whorls, and there are other differences. 
Natica Isabelleana d’Orb. 
Natica maroccana Dillw. (?). Worn young shells. 
Ocinebra cala n. sp. 
Olivancillaria auricularia Lam. Maldonado Bay ; also fossil 
specimens in the Fort wall at La Plata Museum. 
Olivella Puelchana d’Orb. 
Scala elegans d’Orb. (probably). 
