A-1): Highly sclerotized structure consisting of basis capituli, median ventral hypostome
, a pair of long cylindrical shafts, the chelicerae and flanked on each side by a pair of palpi with visible three segments, capitulum shorter than that of , dorsal ridge strongly developed, and both it and lateral margins straight and heavily sclerotized, slightly converging posteriorly, hind margin also straight and transverse.
As blood and tissue fluids pool into the wound, they are sucked up by the hypostome
, which also anchors the tick into the skin by means of the recurved hooks.
, pygidium and thorax are unknown.
CBs are defined as several consecutive pulses, usually arising at the hypostome
, and are through-conducted into the tentacles from the body; the pulses are associated with the contraction of the body column (Passano and McCullough, 1964; Kass-Simon, 1972, 1973).
Ticks feed exclusively on blood, and begin by cutting a small hole into the host epidermis with their chelicerae and inserting the hypostome
into the cut, thereby attaching to the host.
The key character of the 'Corynexochida' is fusion between the hypostome
and the rostral plate, but the condition is often unknown and occasionally known to be different (for instance in Ogygopsis and dinesids; see also Hopkins & Webster 2009 and Robison & Babcock 2011).
For instance, immunoreactivity to the neuropeptide FMRFamide is broadly distributed in cnidarians and has been detected in the head (in both the hypostome
and tentacles), base, and body column of hydra (Grimmelikhuijzen, 1983b; Grimmelikhuijzen et al.
Morph A (pygidia GIT 585-4-1, GIT 585-3-1, Figs 3A, 4O-S; and possibly hypostome
GIT 585-2-1, Fig.
Zooanthellate digestive cells of Myrionema ambionense have two general shapes: columnar from the hypostome
(= cup) region of the hydranth (also called digestive cells here, Fig.
The mouth, or opening to the gastric cavity, is in the hypostome
, the apical part of the head [ILLUSTRATION FOR FIGURE 1B, C OMITTED].
When the hypostome
is touched with a brine shrimp larva the mouth opens and the larva is ingested, and then digested.
The apical end of the planula forms the base of the polyp, the middle region forms the stalk, and the basal end forms the hypostome