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AMERICAN JOURNAL 
rays of color, racliating from thè spire. There are no ribs or 
costag, but occasionally a moderately sharp line or two may be 
observed radiating from thè apex, and impressed, as it ivere, 
from below. The apex is lighter than thè rest of thè shell. The 
interior is extremely polished and brilliant, and only in dead 
specimens is thè mark of thè siphon perceptible without a glass. 
The external colors are visible ivithin, from thè translucency of 
thè shell. The siphonal groove is not visible from thè outside, 
nor does it cause any extension or emargination of thè edge of 
thè shell. The aperture is roundly ovai and thè edge simple. 
Some thirty specimens of this beautiful little species ivere 
found dead on thè Halfmoon beach at Monterey. One was found 
adhering to thè frond of a Laminaria. Dr. Newcomb obtained 
it at Santa Barbara; Mr. Hepburn at San Diego; Mr. Stearns 
at Purissima and Lobitas, San Mateo county, Cai. Among a 
large number of beach shells obtained on thè Gallapagos Islands 
by Dr. Hable, this species vas not uncommon ; thè specimens 
■were generally thinner, lighter colored, and smaller than those 
obtained from further North. When this shell ivasfirst obtained 
at Monterey, in a hurried list of species found by me at that lo- 
cality, I gave it thè MSS. name of vernalis., from thè bright 
green epidermis, and- referred it doubtfully to thè genus Nacella., 
■vvhicli it externally resembles. Being called away by othev du- 
ties to a more northern station, thè MSS. and specimens were 
referred to Dr. Carpenter. At first that gentleman was disposed 
to refer thè shell to a lost species described by Middendorf under 
thè name of Acmoea pileoìus. As thè shell in question has not 
been found north of San Francisco, it is not probable that Mid- 
dendorf ever saw it, and, moreover, I am informed that his type 
specimens do not agree with his diagnosis, and are probably 
young Acmoeas, while his figures differ from this species. 
Dr. Carpenter called my attention to thè mark of thè siphon, 
and a more thorough examination showed that it belonged to thè 
genus Siphonaria. 
A careful examination of thè type specimens in thè Smithsonian 
Cabinet has developed thè following unexpected coincidences : 
Nacella peltoides, Cpr. (S. I. Cat. No. 4023) is exceedingly 
minute, but appears to be identical with this species. The type is 
so young that it is almost colorless, but thè mark of thè siphon 
is perceptible with a magnifier. It is a pity that so inelegant a 
name must be applied to this pretty species.* 
? Nacella subspiralis, Cpr. (S. I. Cat. No. 11,847). A careful 
* The niiclear whorls, usually brokeu off, are preserved in thè unique 
type of subspiralis, and in thè types of peltoides. I also found them on a 
very few specimens from Mty. and Ual. Ids. 
