- Orient the specimen
Photograph of a freshly preserved animal. Note the head and tail region of the animal, as the specimen will appear different after removal of the shell. For humane purposes, ensure that the animal is completely unresponsive to touch before initiating the dissection. See supplies section on how to relax the specimen.
- Remove the animal from the shell
In some cases, it may be possible to remove the dead animal from its shell using curved forceps. If this is not possible, slowly break the shell from the aperture backwards, following the whorls, until the animal can be removed from the shell intact. (It is important to retain the broken pieces of the shell for identification purposes). A pair of needle-nose pliers may be used depending on the size of the animal’s shell.
- Submerge “Shell-less” animal in 75% Ethanol or Water
Diagram showing a Helix species with the shell removed (Figure 06) was provided to assist with the orientation of the specimen. Place the “shell-less” adult specimen in a dish with 75% ethanol or water covering it.
- Uncoil snail and make an incision above the mantle skirt
Slowly uncoil the portion of the animal that was inside the shell to expose its contents. Make an incision just above the mantle skirt as indicated by the broken line in Figure 08. Be sure to make shallow incisions and angle the scissors upwards, and away from the internal organs. Cut as far along the skirt as possible.
- Cut along the length of the thin membrane
Cut along the broken lines as indicated in Figure 10. Avoid all internal organs/structures by only cutting the thin (transparent) membrane. Continue with the incision along the edge of the membrane all the way to the first whorl. This will expose portions of the reproductive and digestive system. Also, cut along the lines indicated in Figure 12 to expose the base of both systems.
- Peel back the membrane to expose the internal organs
Peel back the transparent membrane to expose the internal organs. Continue with the incision made in Figure 12 all the way to the end of the coiled regions of the animal (portion that was retained inside the shell).The animal may be inverted to accomplish this as indicated by the broken lines in Figure 15.
- Remove ovotestis from digestive gland
Slowly tease the ovotestis and the albumen gland away from the digestive gland. Both organs can be carefully separated with a pair of tweezers. Once dislodged, both systems can be separated as indicated in Figure 19.
- Cut forward into the mantle skirt to expose the base of the reproductive system
Rotate the animal unto the side (may have to hold in hands) and cut into the mantle skirt going forward, towards the head. Be sure to make the incision between the ocular tentacles. This cut will expose the basal region of the reproductive system.
The pins can be removed from the specimen for photography or closer examination.
- Detach the reproductive system
Gently separate the reproductive system from the digestive system. Note the genital opening in Figure 22. Make incisions along the broken lines as indicated in Figure 22. Be careful to avoid cutting through the atrium. This incision will detach the entire reproductive system form the rest of the animal (Figure 23). Use an insect pin to gently unravel the vas deferens, bursa copulatrix, oviduct, flagellum, and penis by following the connection to each.
- Treatment for Photography
If a photograph of the reproductive system is required, the structures can be arranged and pinned as desired then fixed in place by immersion in 95% ethanol for approximately 15 minutes. DO NOT leave the reproductive structures in 95% ethanol for an extended period as dehydration and distortion will occur. The pins can be removed from the specimen for photography or closer examination.