Physical characteristics

The most obvious characteristic of cubozoans is the boxlike shape of their bell. The manubrium and mouth are located inside the bell, and the velarium is along the edge of the bell. Pedalia are muscular extensions of the bell and the tentacles are attached to the pedalium. Chirodropids have multiple tentacles attached to each pedalium; carybdeids have only have one tentacle per pedalium. Between the pedalia are the unique sensory structures known as rhopalia. Each rhopalia has a statocyst and six eyes, four simple eyes, and two relatively complex eyes composed of an epidermal cornea, spheroidal cellular lens, and an upright retina. Antisera test ing has revealed that cubozoans possess blue-, green-, and ultraviolet-sensing opsins in the both the small and large complex eyes. The cubomedusan nervous system is complex compared to that of other cnidarians. A diffuse synaptic nerve net throughout the bell region is connected to a subumbrel-lar nerve ring, and nerve processes extend from this ring into the rhopaliar stalks. The processing of visual images probably occurs on this nerve ring.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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