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Mills (1981) gives an example of four hydromedusan hunting behaviors (Figure 3.18) that correspond well with Madin’s general model. The first species, Proboscidactyla flavicirrata (Figure 3.18a) corresponds to the A‐type predator in Figure 3.18: neutrally buoyant with 40–80 tentacles radiating from a globular bell. P. flavicirrata employs a motionless ambush strategy, allowing small zooplankton to enter the “encounter zone” through their own swimming behavior. Its neutral buoyancy makes it an especially effective trap for its plankton prey.

As a congener of Stomotoca pterophylla, Stomotoca atra is a B‐type (see Figure 3.18b) predator. By adding its swimming behavior, we gain a better understanding of how it uses its two long tentacles to hunt. It employs a hop–sink swim cycle to drag its long tentacles up and down through the water column. As it swims and sinks, the tentacles describe a sine curve about the width of the bell and 2 meters from top to bottom. It feeds on large prey (hydromedusae), and it greatly increases the probability of contacting a prey item by its method of interrogating the water column.

The third species, Phialidium gregarium, is the primary prey of Stomotoca atra. P. gregarium also employs a hop–sink feeding strategy but a very different one from that of S. atra. It swims upward, bell uppermost, then sinks down with the bell oriented downward and its tentacles trailing behind (Figure 3.18c). As it does so, vortices are created behind the bell that circulate small prey into the tentacles. P. gregarium would be classified as a C‐type predator in Madin’s Figure 3.17 model.

The last example is Polyorchis pencillatus, a resident of shallow bays where it spends a great deal of its time on the bottom. Its hunting strategy on the bottom is to perch on its tentacles (Figure 3.18e) and use its manubrium to ingest prey from the surface sediments. At intervals it hops up off the bottom, stirring up the sediments, and then back down. Occasionally it swims up to the surface and drifts downward bell up (Figure 3.18d), becoming an A‐type predator in the Figure 3.17 model.

Mills (1981) lists seven factors that contribute to feeding efficiency in medusae: (i) tentacle number and length; (ii) geometry of tentacle posture; (iii) velocity of tentacles moving through water; (iv) swimming pattern of medusa; (v) streamlining effects of the medusa bell on water flow; (vi) diameter of the prey; (vii) swimming pattern and velocity of prey. Together, Mill’s observations and Madin’s conceptual treatment provide a useful framework for examining the feeding strategies of medusae.