580 



SUPPLEMENT. 



entirely internal, and inserted in the posterior part of 

 the body. 



All the species of this division are fossil. See the 

 note on Organic Kemains, vol. i. p. 22. 



FAMILY ir. NAUTILACEA. 



Shell disciform, with a central spine, and short cells, 

 which do not extend from the centre of the circumfer- 

 ence. 



Nautilus Pompilius, pi. 31, f. 3, and pi. 24, f. 63. 

 The other genera are fossil. See the note on Organic 

 Remains. 



FAMILY in. RABIOLACEA. 



All the genera are fossil. See the Note on Organic 

 Remains, vol. i. p. 2227. 



FAMILY iv. SPIIERULACEA. 



Fossil, except one species found near Corsica, which 

 is so minute that the animal has not been ascertained. 

 See as above. 



FAMILY v. CRISTACEA. 

 All the species are fossil. See as above. 



FAMILY vi. LITUOLACEA. 



Shell partially spiral; the last volution continued in a 

 straight line. Spirula Peronii, pi. 31, f. 4. Animal a 

 cephalopode, pi. 24, f. 2. The body or that part which 

 inhabits the shell, a. 



FAMILY vii. ORTHOCERATA. 



Animals of the genera unknown. See the Note on 

 Conchology, p. 350358. 



ORDER III. TRACHELIPODA. 



Body usually spirally convoluted, and separated from 

 the foot, which is free, flat, and attached to the neck 

 at its base for the purpose of locomotion; the body 

 always enveloped by a spiral shell. 



SECTION I.-ZOOPHAGOUS TRACHELIPODA. 



FAMILY i. INVOLUTA. 



Shell destitute of a canal, but with the base of its 

 aperture notched or effuse, and its volutions broad, com- 

 pressed, and rolled up in such a manner, that the last 

 nearly covers all the others. Conus genera/is, pi. 24. f. 3. 

 Cypraea Europea, pi. 24. f. 8. Buccinum undatum, pi. 24, 

 f. 19, 20. The extracted animal; a a, the foot; 6, the 

 head; e, a kind of platform raised above the thoracic 

 cavity, on which the point of the boring trunk rests. 

 This organ is represented at f. 31, 32, and 33. d, d, d, 

 the cavity of the thorax; e, the mantle; /, the rectum; 

 </, the stomach; li, the heart, thrown below, and to the 

 right side of its natural situation, to allow the opening 

 of the tube to be seen; i, the respiratory trunk; k, the 

 organs of the muscles of the boring trunk; I, the course 

 of the tube by which the foot is supplied with water; 

 w, its termination; f. 34, magnified representation of the 

 stomach and alimentary tubes; a, the throat; b, the 

 outer coating; c, the alimentary canal; rf, the opering 

 from the stomach. 



FAMILY 11. COLUMELLARIA. 



No canal at the base of the aperture, but asubdorsal 

 notch more or less apparent, and a fold upon the colu- 

 mella. Valuta scapha, pi. 31,f. 14. The animal has 

 a large thick and fleshy foot, and the head is provided 

 with a vail, from the sides of which issue the tentacula: 

 the proboscis is rather long, and there is an appendage 

 on each side of the base of the siphon. When the pro- 

 boscis is extended, it can bend in all directions, by 

 neans of the retractor muscles, acting with opposing 

 forces. This interesting mechanism is illustrated by 



o2, wherein the proboscis is represented retracted 

 about a half; the external cylinder, a, is seen envelop- 

 ing a portion of the inner one, 6, the point of which c 

 * the termination of the proboscis; the muscles which 



draw it within the body, d d, are in a state of contrac- 

 tion, and at e is represented the great annular muscle, 

 which pushes forward the inner cylinder, and conse- 

 quently lengthens the organ. 



FAMILY in. PURPURIFERA. 



Shell with a short canal ascending posteriorly, or 

 with an oblique notch at the base of its aperture, di- 

 rected backwards. They are all operculate. Purpuru 

 lapillus, pi. 24, f. 79. 



FAMILY iv. ALATA. 



Shell with a greater or less canal at the base of the 

 aperture, of which the right lip changes its form as the 

 animal advances in age, and has a sinus at the lower 

 part. Strombus Succinctus. 



FAMILY v. CANALIFERA. 



Shell with a canal more or less long at the base of 

 the aperture, and of which the right margin does not 

 change its form as the animal advances in" age. Mu- 

 rex acantliopterus, pi. 31, f. 32. 



SECTION II. PHYTIPHAGA. 



Destitute of projecting siphon, and respiring general- 

 ly by an orifice, furnished with jaws, and feeding on 

 vegetables, shell with the aperture entire, and without 

 any notch or canal. Many of the species live upon 

 land, and respire air, while others inhabit fresh water, 

 either stagnant or running. Many are marine. Some 

 families are furnished with an operculum attached to 

 the foot of the animal. 



FAMILY i. TURBINACEA. 



Shell turreted or conoid, having an oblong or rounded 

 aperture, not widened, and the margin disunited. Tur- 

 bo smaragdm, pi. 31 , f. 45. Turbo littoreus, pi. 24, f. 13. 



FAMILY n. SCALARIDES. 



Shell devoid of plicae or folds on the columella; the 

 margins of the aperture are united in circular forms. 

 Scalaria coronata, pi. 31, f. 51. 



FAMILY in. PLICACEA. 



Shell with the aperture not widened, and folds on the 

 columella. Tornatellafiammid^ pi. 31, f. 54. 



FAMILY iv. MACROSTOMA, 



Shell auriform, with the aperture very wide, and the 

 margins disunited; destitute of columella and opercu- 

 lum. Haliotis tuberculata, pi. 31, f. 55, and pi. 24, f. 

 12. Sigaretiis Haliotoideus, pi. 24, f. 42. Shell con- 

 cealed in the mantle; TO, the membranous shield under 

 which the shell is concealed; n, a sinus through which 

 an arm is sometimes protruded; o, the tentacula, at the 

 base of which the eyes are placed. 



FAMILY v IANTIIENIA. 



Shell gibbous, conoidal, thin, transparent, aperture 

 triangular, columella straight, surpassing the base of 

 the right margin ; destitute of an operculum. lanthenu 

 cocigua, pi. 31, f. 59. 



FAMILY vi. NERITACEA. 



Shells semiglobular or oval, destitute of a columella, 

 and the left margin edged and transverse, provided with 

 an operculum; inhabit fresh waters and the sea. 



Natica monilifcra, pi. 24, f. 35. A front view, with 

 tentacular head and mantle reflected; c, the head; f. 

 37, a view of the head from beneath ; f. 38, one of the 

 cartilaginous jaws. Neritinafluviaiilis, pi. 24, f. 18. 



FAMILY vn. PERTSTOMIDA. 



Shell conoid or sub-conoid with an operculum, and 

 the margins of the aperture united. All the species 



