Zoological Illustrations/VolIII-Pl157



effusa,

Ribbon Apple Snail.

—See Pl. 103.


 * A. testâ globosâ, lævi, fasciis purpureo-fuscis cinctâ; spirâ depressâ, apice prominente; aperturâ angustâ; umbilico magno, profundo; columellâ obsoletâ.


 * Shell globose, smooth, with purple brown bands; spire depressed, the tip prominent; aperture narrow; umbilicus large, deep; pillar obsolete.


 * Helix glauca. Linn. Dillw. 918. Helix ampullucea, (var. γ) Gmelin, 3626. Bulimus effusus. Brug. p. 296. No. 1.


 * Lister, 129. 29. Seba, tab. 38. f. 39. tab. 40. f. 3. 4. 5. (optimè.) Martini, 9. tab. 129. f. 1144-5. Knorr, 4. tab. 5. f. 3.


 * Lam. Syst. 6. 2. p. 178. 5.

I concur with Mr. Dillwyn in believing that this shell is the Helix glauca of Linnæus; but, as it is now removed to another genus, I think no real advantage would result from continuing its original specific name; particularly as the identity may be questioned by others, without a chance of the question ever being settled: the adoption of the specific names given to species slightly or incorrectly described by the older naturalists, inevitably tends to increase the original obscurity, in all cases where the point cannot be cleared up. A. effusa may be distinguished from all others by the columella being nearly obsolete; this part existing only in the two terminal whorls of the spire. This species therefore forms a transition to the Planorbes: there is a variety, with narrower stripes, double the size of that here figured.

luteostoma,

Yellow-mouthed Apple Snail.


 * A. testâ globosâ, striatâ, olivaceâ, lineis remotis fuscis fasciatâ; spirâ levatâ, apice acuto; aperturâ effusâ intus marginatâ; umbilico magno.


 * Shell globose, striated, olive, with remote transverse brown lines, spire elevated, the tip acute; aperture wide, within margined; umbilicus large.

The umbilicus of this shell is not so deep as the last, but is larger than in any other known species; the columella is likewise perfect, and the aperture is wider and more oblique than in A. effusa.