. Elements of zoology, to accompany the field and laboratory study of animals. Zoology. 214 ZOOLOGT shown by the enormous variabihty of individual species. Thus in our own country a species, Helix nemoralis, introduced from Europe, has produced at Lexington, Virginia, 385 varieties in an area not over one-half mile in extent. These variations consist of different combinations of ground color and of stripes on the shell. But the wTm animal itself is eciuallj^ variable, for any W|F species of Helix, collected in large numbers, I will show individuals having abnormalities Fig. 201. —Meiam- both i
. Elements of zoology, to accompany the field and laboratory study of animals. Zoology. 214 ZOOLOGT shown by the enormous variabihty of individual species. Thus in our own country a species, Helix nemoralis, introduced from Europe, has produced at Lexington, Virginia, 385 varieties in an area not over one-half mile in extent. These variations consist of different combinations of ground color and of stripes on the shell. But the wTm animal itself is eciuallj^ variable, for any W|F species of Helix, collected in large numbers, I will show individuals having abnormalities Fig. 201. —Meiam- both in regard to the number of tentacles pus, the salt-marsh ^t^^ gf py^g ypon each tentacle. Besides .snail. Nat. size. Piioto. by W. H. Helix, a very abundant cosmopolitan land pulmonate is Pupa.' The shell is many times whorled, and has a blunt apex. Being of small size, it is, however, less commonly known. It is found in woods under leaves or in old stumps and decajdng logs, where it feeds. It is a lover of darkness, moisture, and contact. Intermediate between the terrestrial and aquatic pulmonates is the family Auriculidae, the members of which live on the seashore, in salt marshes (Fig. 200), or on rocks where they may even he immersed in brackish water at high tides. One of the commonest forms is Melampus (Fig. 201), found among the roots of marsh-grass. Of the aquatic pulmonates three genera are common and easily chstinguLshable. Limnaea,^ the " pond snail," is common in. Fig. 202.— Left Physa, hetero- s(rop}ia, the left-handed pond snail. Right, Limna!a, the right- handed pond snail, with the apex eroded off as is usually the case in adult shells. Nat. size. Photo, by W. H. C. P. A little girl or doll. 2 From limne, a Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Davenport, Charle
Size: 2012px × 1241px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1911
