The betuline cone (Conus betulinus) is a large predatory and venomous cone snail, related to the textile cone.
It has a heavy shell that grows to up to 17 cm in length, and is distributed across the Indo-Pacific. The snail itself is velvet black and crawls around on a broad foot hunting worms.
In Hong Kong it occurs on sandy bottoms down to 5 m and in 1985 was still regarded common, although I haven’t ever seen a live one locally (yet!)
In contrast to the textile cone, the toxicity of the betuline cone is low. The toxins of cone shells are known collectively as conotoxins and act on the ion-channels regulating cells activities as well as on neurotransmitter functions.