Snail Studies in Elementary Biology

Abstract

For many years the snail has been overlooked as a desirable specimen for elementary study. In the usual high school laboratory snails are found in every balanced aquarium. Their function as scavengers is mentioned briefly. Some instructors include the snail in the general classification system. That is just about all that the beginning student learns about them. A survey of modern laboratory manuals and workbooks substantiates this. There is no mention of the snail as a specimen for student study. The usual reason given for this omission is that the snail is too difficult for the beginner to dissect. To overcomiie this a series of simplified studies has been devised for use in the high school biology course. These may be adapted to the junior college or college level. The studies were motivated by the general belief that the more familiar a laboratory specimen, the more interest is displayed by the students. In most localities there is ample material available. All common land and pond snails are suitable for general observation. For dissection purposes the larger varieties are preferable. Most of the commercial biological supply houses are able to furniish a wide assortment. Some of the more familiar varieties for study are the landl snail Helix pomtatia and the fresh-water types Physa (pond snail) ; Litnnea auricularia (African paper shell) ; Lintnea peregra. (wandering snail) ; Limtnea palutstris (marsh snail); Planorbis corneus (black or brown ramshorn) ; Planorbis corneus rubra (red ramshorn) ; Paludina vivipara (live-bearing snail); Ampullaria gigas (four-horned snail); Vtviparous (intertextus) contectoides (Potomac green snail) and Vivipacrotus malleatus (the black Japanese snail). Snails of the land type are conveniently studied in a woodland terrarium. Woodlandc mosses, ]iverworts andl native ferns, growing in humus or dampened leaf mold, serve as an adequate environment. Most of the land varieties enjoy shade and a little moisture. A number of these feed on the decomposing animal matter, or may be given fresh lettuce leaves.