52 THE NAUTILUS. 
Senegambian specimens I find the hinge quite different from Joannis” 
figure, and essentially similar to that of American species. 
The first of the latter was described by Morelet in 1851, from 
Porto Rico, under the name of ©, americana. It differs from the 
African species by its smaller and more delicate shell, its more 
quadrate form and proportionately shorter ligament. Some species 
reported from the Philippines by Sowerby I have shown to have a 
different hinge and separated under the name of Joannisiedla. 
The first continental American species was obtained by Hemphill 
in the marshes of southwest Florida (Marco, Boca Ceiga Key, and 
the Everglades) where it affects brackish, or even tolerably salt 
water, indifferently. This I named in manuscript C. floridana (ef. 
Bull. 37, U. S. Nat. Mus., 1889, No. 217, p. 50). Lastly a fine 
Pliocene species was obtained by Mr. Willcox and myself from the 
marls of the Caloosahatchie River in south Florida. 
Diagnoses of the two latter follow. 
Cyrenoidea floridana (Dall, MS., 1889) n.s. 
Shell rounded, small, thin, very delicate, whitish or translucent 
with a pale, silky, yellowish, dehiscent epidermis ; surface smooth, 
or sculptured only by incremental lines; interior margin smooth, 
polished ; the visceral area with a dull, more or less punctate sur- 
face ; pallial line indistinct, often broken, not sinuous; ligament 
short, brownish, external ; hinge as in C. duponti but more delicate. 
Largest specimen, lon. 13°5, alt. 12°5, diameter 8:0. 
The range of the species, as far as known, is from Brunswick 
Georgia, south to the Everglades on the east, and, on the west, north 
to Charlotte Harbor and vicinity. 
The animal is distinctly Lucinoid, the foot is long, slender, filiform 
and with an ovate, swollen distal termination. 
Cyrenoidea caloosaensis n. s. 
Shell large, thin, resembling C. floridana, but coarser, with ruder 
concentric sculpture, sometimes approaching undulations; more in- 
equilateral, the anterior part relatively smaller and shorter, the 
anterior left bifid cardinal tooth proportionately much shorter than 
in either of the other species of the genus. Lon. of shell 30°9, alt. 
27:0, diameter 17-5 mm. 
The shell is known, so far, only from the Pliocene marls of south 
Florida. 
All the species are very similar to one another, and differ only in 
minor details of form and hinge. They would, as a rule, be taken 
for Diplodontas except for the differences of the hinge. 
