The venom apparatus of Conus magus.

Abstract

Abstract A syncytial epithelium lines the lumen of the tubular venom duct of Conus magus Linne. Small spherical bodies are elaborated in vacuoles in this epithelium anteriorly near the junction of the duct with the pharynx. The vacuoles and contained spherical bodies enlarge considerably causing the duct epithelium to grow posteriorly towards the terminal venom bulb. About a quarter of the distance to the bulb from the junction of the duct with the pharynx, venom bodies which possess obvious sheaths and which are derived from the spherical bodies appear. Each of these mature venom bodies possesses a core which contains carbohydrate, protein, protein-bound NH2 groups and 3-indolyl derivatives. In the remainder of the duct the ratio of mature to immature venom bodies increases with distance from the anterior end. Differences in the degree of development of the venom bodies can be correlated with differences in the toxicity and pharmacological properties of venom extracted from anterior and posterior regions of the duct. It is postulated that venom containing mainly mature venom granules from posterior regions of the venom duct is injected via a hollow radular tooth into prospective prey.