Greenhouse slug

The body of Milax gagates is an even dark grey to black, although it has somewhat lighter sides. There are no pigment spots. The mantle is relatively large (35-40% of body length), with distinct grooves. The keel is prominent between mantle and posterior end. Skin sculpture is weak. There are 16-17 grooves between keel and pneumostome. The sole of the foot has blackish lateral zones and a lighter medial zone. Milax gagates is up to 50 mm long. Preserved specimen have a length of 25–30 mm and a width of 6–8 mm. The weight of adult slugs ranges from 991.2 mg to 3308.0 mg. Reproductive system: The penis is rounded, and half as long as the epiphallus. The epiphallus is slightly widened and truncated (as if cut off) at its end. the vas deferens is short (usually not longer than epiphallus), opens asymmetrically at the truncated end of the epiphallus. The atrium is short, and not widened. The accessory gland consist of several elongate glands and is connected to the atrium by some 20 short coiled tubular ducts. The stimulator is narrow, conical, slightly flattened at its end with some papillae. The stimulator of the similar species Milax nigricans has more papillae situated at its base and not near its free end.