Slug Dissection

Step 1

  • Note general location of internal organs (dorsal view)

These are generalized diagrams of the digestive and reproductive systems. Both systems occupy most of the animal and in many cases are closely associated. Please note that the size, location and relative position of the reproductive organs may vary depending on the species.

step 1 View from dorsal surface

Step 2

  • Orient the specimen

Photograph of a freshly preserved animal. Submerge the relaxed, extended adult specimen in a dish with 75% ethanol or water. Note the head and tail region of the animal, as the specimen will appear different after removal of the body covering or mantle. 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.

step 2 Figure 02

Step 3

  • Remove the foot of the animal by cutting along the sole

Make a shallow incision near the tip of tail using a pair of sharp dissecting scissors. Angle scissors upwards and proceed with the incision along the foot of the animal. The incision should be made just above the foot fringe, groove, or where the body or mantle of the animal meets the foot. Cut towards the head of the animal (on both sides) to remove the entire foot.

step 3 Figure 03 step 4 Figure 04 step 5 Figure 05 step 6 Figure 06 step 7 Figure 07 step 8 Figure 08 step 9 Figure 09

Step 4

  • Remove the body covering and/or mantle of the animal

Gently peel the body or mantle back to expose the contents of the animal. Begin at the tip of the tail and work towards the head. Be sure to cut between the body or mantle and the heart to remove the body covering. Also, make incisions along the margin of the foot, to avoid cutting internal organs and eyestalks. Remove the body covering or mantle.

step 10 Figure 10 step 11 Figure 11

Step 5

  • Separate the digestive gland from the albumen gland

Separate the digestive system from the reproductive system by gently peeling away the digestive gland from the albumen gland.

step 12 Figure 12 step 13 Figure 13

Step 6

  • Remove the ovotestis from the digestive gland

Gently remove the areas of the digestive gland that cover the ovotestis. The ovotestis is often embedded in the digestive gland but is easily identified, as it is typically a different color (or shade). Make incisions along the sides of the hermaphroditic duct (Figure. 14) to remove all lateral connections to the digestive gland. The animal may need to be inverted for these steps.

step 14 Figure 14 step 15 Figure 15 step 16 Figure 16

Step 7

  • Remove heart and kidney to reveal bursa copulatrix

Gently remove the heart and kidney to reveal the bursa copulatrix and head region (including the optic region)

step 17 Figure 17 step 18 Figure 18 step 19 Figure 19

Step 8

  • Separate the reproductive system from the digestive system

Orient the animal as illustrated in Figure 19 so that the reproductive system is above the digestive system. Tweezers can then be used to either pull the two systems apart along the dashed lines (Figure. 21) OR the structures can be slowly teased apart beginning at the buccal mass (removing the eye stalks and crop).

step 20 Figure 20 step 21 Figure 21 step 22 Figure 22

Step 9

  • Unravel the reproductive system

Figure 23 displays the entire reproductive system of the animal. The structures are compressed and intertwined at this stage and need to be teased apart. Please Note: the red color of the atrium is not common to all slugs. Use an insect pin to gently unravel the vas deferens, bursa copulatrix, oviduct, and penis by following the connection to each.

step 23 Figure 23 step 24 Figure 24 step 25 Figure 25

Step 10

  • 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.

step 26 Figure 26 step 27 Figure 27