In the absence of segmentation, the positioning of the eyes, limbs and gonopore on the idiosoma provide the only locational guidance.
12.
Millipede gonopods do not produce sperm directly, but rather gather sperm produced from a gonopore on the base of the third body segment.
13.
The gonads of " Psilaster andromeda " are located at the base of the arms and each one opens through a single gonopore.
14.
On their ventral surface they have a partial head, mouth, mantle, mantle cavity, foot, gills, gonopore, nephridiopore and anus.
15.
The gonopore is homologous to the cloaca of females, but in most species has no connection to the vestigial digestive system, which lacks an anus.
16.
The male gonopore is, however, adorned with a " penile process ", which is straight and serrated, with a small " hairbrush ".
17.
During spawning, females forcefully expel all their eggs into the water in a single burst from their gonopore ( the opening where gametes are released ).
18.
The movement of the female gonopore to the sternum defines the clade Eubrachyura, and the later change in the position of the male gonopore defines the Thoracotremata.
19.
The movement of the female gonopore to the sternum defines the clade Eubrachyura, and the later change in the position of the male gonopore defines the Thoracotremata.
20.
The position of the gonopore varies considerably between groups, but is generally constant within groups, allowing its position to be used as a " segmental marker ".
