Physical Description and Anatomy
The most obvious feature of Diphyes bojani is the transparent, bullet-shaped swimming bell (the nectophore, see image below). The nectophore can measure up to 14mm long and has ridges running from the base to the tip (Quark 2007). Inside the nectophore are two chambers; the nectosac (shown in red), and the hydroecium (shown in blue). The nectosac has a muscular ring at the bottom, which is used for jet-propulsion. The hydroecium is approximately one third of the height of the nectophore and ends next to the stomatocyst (shown in green); a small chamber filled with oil for buoyancy, extending towards the nectophore apex.
Attached to the inside of the hydroecium is a long stem (or siphonosome) with clusters of individual zooids (cormidia; shown in pink). The siphonosome can be extended (when it resembles the tail of a kite) or wholly or partially retracted inside the hydroecium.
The zooids are highly specialised and cannot exist separately. Each cormidium has a gastrozooid, a gonophore and is covered by a shield-like bract for protection. The gastrozooid captures and digests food and shares nutrients with other zooids. It has a small tentacle (see image, below). The gonophore is the reproductive system, however while attached to the siphonosome, it is not sexually mature.
The cormidia and the tip of the stomatocyst are pale pink under bright light, however they appear iridescent green under low light conditions, and fluoresce bright green under green fluorescent protein (see image, below).
Using a fluorescent microscope, I examined the structure of the bottom of the nectophore. The image below shows the muscular ring of the nectophore. Muscle fibre is shown in green, and the bright blue dots are nuclei.
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