The Conchologist’s First Book — Edgar A. Poe, 1839 — reading text

requisite in order to ascertain which is really the upper side of the shell, for it is on that side the spiral turns are to be taken from the centre or apex; and, in most instances, this is to be determined by the oblique direction of the aperture to the under part, where the lip rarely extends so far as on the upper part. In fixed shells, such as Serpule, there is no difficulty, as the side which is sessile must be considered as the base or under part. Thus in the Serpula Lucida the fixed part is some- times very small, and the mouth protends spirally upwards, in a contrary direction to the sun; and therefore must be considered a reversed or heterostrophe shell, the same as if the volutions nearest the mouth had turned laterally upon the centre or fixed ones. This shell, indeed, is most frequently found with regular lateral volutions; and though subject to great variety, with respect to contortions, it invariably turns the aperture one way. In some species of Nautilus, however, there can be no rule to ascertain whether the shells are dextral or sinistral; for when the aperture is exactly central, the lip embraces the body equally, and the sides of the shell are similar. In others of that genus, as in N. Beccarii and Beeccarii perversus, two shells, the principal dis- tinction of which is the contrary turn of their volutions, it is easily determined by the convexity of the upper side, and, of course, the aperture being placed somewhat beneath. Chambers are the cavities divided by partitions, at regular or irregular intervals; as in the Nautilus. Plate III. fig. 11, ww www. In some of the Serpula there are also divisions, but they are not regular as in the Nautili; and besides, they differ from them in being devoid of a siphunculus or communication between the chambers, the animal forms a complete partition, and adds to its shell, which it would appear to be necessitated to do from its body growing too large for its abode. Several of the Patelle have chambers formed of laminous par- titions, subspiral cells, or processes ; these in general lie horizon- we EXPLANATION OF THE PARTS OF SHELLS. 19 tally, and are quite open at one end, as in the Patella testudinaria, the Crepidula, and Calyptrea. Umbilicus is in general a circular perforation in the base of the lower whorl, or body, of many univalve shells. This is com- mon to most of the Trochi, in some species of which it penetrates from the base to the apex: widest at the base, and gradually tapering to the top. Plate III. fig. 1. zw. Sub-umbilicated shells are those which have the umbilicus covered in a greater or less degree by a thin process; which, in some, almost entirely closes the opening or mouth. This charac- ter is most commonly to be met with among species of Buccinum and Murex. Shells which have no umiilicus are termed imperforate. Siphunculus is that small round perforation which forms a communication between the chambers of the Nautili, and pene- trates through the whole spire of the shell. Plate III. fig. 11. x. Varices are transverse ribs which cross the whorls of shells in some species of Buccinum, Murex, and Tritonia, and exemplified in the Cassidaria. Varices are formed by the. periodical growth of the shells, these being the margin of the outer lip, to which the animal has attached its periodical enlargements. In some spe- cies they have more the form of sutures than ribs; this is owing to the margin of the outer lip being but slightly developed. Ribs are those longitudinal and transverse protuberances which are in many of the univalve shells. Plate III. fig. 12. PUT & Teeth of univalves, or tooth-shaped protuberances, are fine white lamine, or ridges, running spirally backwards, in a parallel direction to each other; those on the exterior lip may, in most instances, be traced through the outside of the shell, and are nearly alike in length. Plate III. fig 13. a. Epidermis is a skin, or cuticle, covering the exterior surface of shells, destined by nature to protect their surface from being injured. It is membranaceous, somewhat similar to the perios- teum which covers the bones of animals, This substance is the production of the animal inhabiting the shell; it is uniformly observed in some species, and not at all in others, Shells with a rugged or uneven surface have almost always this epidermis. In 20 INTRODUCTION. some it is strong, laminated, velvety, fibrous, or rough, often beset with long hairs, and in others very thin, smooth, and pellucid, and admits the colours of the shell to shine through it. In some species it is so dusky that it entirely obscures the beautiful colouring of the shell beneath. Although many shells are very beautiful, even with this cuticle on them, they are much more so when it is removed ; but I would by no means advise the collector of shells to remove it, unless he may have several duplicates of the same species; and then he may do it by way of variety. It is always preferable, however, to keep them in a state of nature. A shell with epidermis is represented in Plate III. Y; and the effect of the epidermis removed at J. All other protuberances, furrows, &c. will be described at the end of this work, in a Glossary of Terms used in the Science. s DESCRIPTION OF PLATE IV. HINGES OF BIVALVE SHELLS. Fig. 1. Hinge of the Unio pictorum, a Primary tooth, c c double teeth. e Fig. 2. Hinge of the Solen. 6 Lateral teeth. Fig. 3. Hinge of the Lucina radula,a @ Primary teeth, n cartilage. Fig. 4.. Hinge of the Cardium. 6 Lateral tooth, d d middle teeth, 7 7 spines. Fig. 5. Hinge of the Lutraria. Fig. 6. Inside of ‘both valves of the Denazx trunculus. A is the left valve, and B is the right valve, 6 lateral teeth, 6 primary complicated tooth, or cleft in the middle, m m crenulated margin. Fig. 7. Hinge of the Venus, a a Primary teeth, 6 lateral tooth. Fig. 8. Hinge of Spondylus zederopus, f f incurved teeth. Fig. 9. Hinge of Isocardia Cor. Fig. 10. Hinge of the Pectunculus, & k numerous small teeth ; the distinguishing characteristic of the genus Arca. Fig. 11. Hinge of the Pecten, » cavity of the hinge, A supe- rior ear, z inferior ear. Fig. 12. Hinge of Anomia Ephippium. CLASSIFICATION. CLASS I. ANNUL bo TA. FOUR FAMILIES. Fam. 1, Dorsalia. Two genera. 1. Arenicola. 2, Siliquaria. “ce Species 1 5 ‘2. Maldania. ‘Two genera. 1, Clymene. 2. Dentalium. 3. Amphitritea. 1, Pectinaria. 2. Sabellaria. 3. Terebella. 4, Amphitrite. 4, Serpulacea. 1, Spirorbis. Species 2. Serpula. 3. Vermilia. 4, Galeolaria. 5. Magilus. Species. 1 ““ 14 Four genera. Species 2 “ce ce 4 13 mn Five genera. 6“ 2 6s NwWnonan cc CLASS IT. CIRRHIPEDA. ONE FAMILY. 1. Cirrhipeda. 1. Tubicinella. 2. Cor onya. 3. Balanus. 4. Acusta. 5. Caeusia. 6. Pryrgoma. 7. Anatifera. 8. Pollicipes. 9. Cineras. 10, Otion. Ten genera. Species 1 73 4. g 29 6c 4 “é 3 “ce 1 ‘ 6 “ce 5 “ec 1 6é 9 Fam. 1. Tubicola. Six genera. 1. Aspergillum. Species 4 2. Clavagella. “s 1 3. Fistulana. cS 4. 4, Septaria. “5 2 5. Teredina. i 2 6. Teredo. of 3 2. Pholadaria. 'Two genera. 1. Pholas. Species 13 2. Gastrochena.. “ 3 3. Solenea. Four genera. 1. Solen. Species 19 2. Panopea. s 1 3. Solecurtus. ‘ 3 4, Glycimeris. ¢ 2 4, Myaria. ‘Two genera. 1. Mya. Species 4 2. Anatina. = 10 5. Mactracea, Seven genera. 1. Lutraria. Species 11 2. Mactra. “634 3. Crassatella. GS eR | 4, Erycina. ae ] 4. Ungulina. ‘ 2 6. Solemya. es 2 CLASS Ill. CONGHIFERA. TWENTY FAMILIES, 7. Amphidesma. “ 36 . Corbulacea. Two genera. 1. Corbula. Species 13 2. Pandora. “s 4 . Lithophaga. Three genera. 1. Saxicava. Species 5 2. Petricola. Gt. a2 3. Venerirupis, és 8 * 22 a. 9. 10. 11, 12. 13. 14, 15, ® CLASSIFICATION. Fam. Nymphacea. Ten genera. | 16. Mytilacea. Three genera. 1. Sanguinolaria. Species 5 1. Mytilus. Species 36 2. Psammobia. or LS 2. Modiola. eS 25 3. Psammotea. Se 3. Pinna. xe 15 4, Tellina. “« 655 |17. Mallacea. Five genera. 5, Tellinides. « 1]. 1. Crenatula. Species 7 6. Corbis. ber ee 2. Perna. ss 12 7. Lucina. “22 3. Malleus. a 6 8. Donax. “28 4, Avicula. ‘ 14 9, Capsa. Nba: 5. Meleagrina. x 2 10. Crassina. “ 1118. Pectinea. Seven genera. Conchacea. Seven genera. 1, Pedum. Species 1 1, Cyprina. Species 9 2. Lima. ng 7 2. Cytherea. 89 3. Pecten. Po do hf 3. Venus. “i 99 4, Plagiostoma. “ 10 4. Veniricardia. c.. 15 |e 5. Plicatula. ae 5 5. Cyclas. Al 6. Spondylus. ue 26 6. Cyrena. peed 1 te Ou opsis. . 2 7. Galathea. “« 1119. Ostracea. Six genera. Cardiacea. Five genera. 1. Ostrea. Species 81 1, Cardium. | Species 64 2. Gryphea. a 1 2. Cardita. « 25 3. Vulsella. me 7 3. Cypricardia. “ 7 4. Placuna. Re 5 4, Hiatella. 4“ 2 5. Anomia. “ 9 5, Isocardia. © athye 5 6. Crania. ¥ 1 Arcacea. Four genera. 20. Brachiopoda. Three gen. 1, Arca. Species 46 1. Orbicula. Species 3 2. Cucullea. “: 2 2. Terebratula. <“ 49 3. Pectunculus. “ 31 3. Lingula. e 1 4. Nucula. Fe 44 Trigonacea. ‘Two genera. ee aes 1. Trigonia. | Species 16 2. Castalia. masks 1 Naiadea. Four genera. CLASS IV. 1. Unio. Species 167 2 Hyria. s“ 2 MOLLUSCA. 3. Anodonta. & 49 WA dioih a 6 TWENTY-THREE FAMILIES. Chamacea. Three genera. | 1. Pteropoda. ‘Six genera. 1. Diceras. Species 1 4, Hyalea. Species 2 2. Chama. e 25 2. Clio. 2 2 3. Etheria. ¢ 5 3. Cleodora. i 2 Tridacnea. ‘lwo genera. 4, Limacina. és 1 1, Tridacna. Species 7 5, Cymbulia. ™ l 2, Hippopus. ROHS cin 6. Pneumodermon “ 1 CLASSIFICATION. Fam. 2. Phyllidiacea. Six genera. 3. Chiton. ‘60 4, Patella. » “45 5. Umbrella. Re 2 6. Pleurobranchus. “ 2 3. Calyptracea. Seven gen. 1, Parmophorus. Species 5 2. Emarginula. % 5 3. Fissurella. fe) 20 4, Pileopsis. 5 5 5. Calyptrea. = 8 6. Crepidula. ome 7. Ancylus. 23 3 4. Bullacea. Three genera. 1. Acera. Species ] 2. Bullea. 2 | 3. Bulla. .re L£ 14 5. Aplysiacea. 1, Dolabella.’ Species 2 | 2. Aplysia. ces Y 6. Limacina. Five genera. | 1, Limax. Species 5 2. Vitrina. 3 3. Testacella. | - 2 4. Parmacella. - 2 LP 8. 1, Phyllidia. Species 3 2. Chitonellus. “ 2 Two genera. 5. Onchidium. Ks 2 Colimacea. Eleven genera. 1, Helix. Species 168 2. Carocolla. 22 3. Achatina. 8622 4, Anostoma. ‘ 3 5. Helicina. Bie LG 6. Pupa. « 2333 7. Clausilia. “615 8. Bulimus, By Gk 9. Succinea,. ee 7 10. Auricula. fry AG 11. Cyclostoma. > dO Lymnacea. Three genera. 1, Lymnea. Species 17 2. Physa. ‘s 6 3. Planorbis. . 14 23 Fam. 9. 3. Melanopsis. & 3 10. Peristomiana. Three gen. 1, Valvata. Species 2 2. Paludina. ae It 3. Ampularia. Py LS 11. Weritacea. Four genera. 1. Neritina. Species 28 2. Nerita. eo 20 3. Navicella, 3 4 4, Natica. ¢ - 36 12. Janthinea. One genus. 1. Ianthina. Species 3 13. Macrostomiana. Four gen. 1. Sigaretus. Species 4 2. Stomatella. ES 5 3. Stomatia. me 2 4, Haliotis. € 4° £9 14, Piicacea. Two genera. 1. Tornatella. | Species Gs 16. 17. . Scalarina. Melanianw. Three genera. 1. Melania. Species 29 2. Pirena. & ‘5 2. Pyramidella. e 6 Three genera. 1. Sealaria. Species 14 2. Vermetus. - 2 3. Delphinula. eran ae T'urbinacea. Eight gen. 1. Solarium, Species 15 2. Trochus. co" 107 3. Monodonta. to 34 4, Turbo. «~ 43 5. Planaxis. “ 4 6. Phasianella. oe ee 7. Turritella. ay 8. Rotella. a 7 Canalifera. Eleven gen. 1. Cerithium. Species 47 2. Pleurotoma. ae 3. Turbinellas © “ 23 4, Cancellaria. “« 68 5, Fasciolaria. “6 15 6. Fusus. cur 79 7. Pyrula. we 96 ~ 24 CLASSIFICATION. Fain. Fam. 8. Struthiolaria. Species 2 | 20. Columellaria. Five genera. 9. Ranella. “a a 1. Columbella. Species 14 10. Murex. ea a) 2. Mitra. e680 11. Triton. ett o4