Fig. 4. A. aculeatus, scanning electron micrographs. (A) Lateral view, showing the gland opening (right arrow) and the carapace channel (middle and left arrows). (B,C) Close-up view of side of animal at base of legs 1 to 3. In B, the animal is tilted to expose the right-hand ventral surface of the animal, bringing into view the cleft (arrow) between the coxae of legs 1 and 2, along which the oral effluent is conveyed. In C, the gland opening (arrow) is shown in relation to the two spines (asterisks) projecting from the coxae of leg 2 that presumably help direct the oral fluid past the gland opening; the notch immediately behind the gland opening serves to convey the liquid onto the carapace channel.