The cercaria is just visible to the naked eye and has an oval or discoidal body and usually a long tail of variable form.
In the so-called Selenariidae, probably an unnatural association of genera which have assumed a free discoidal form of zoarium, they may reach a very high degree of development, but Busk's suggestion that in this group they "may be subservient to locomotion" needs verification.
Discoidal; 10, sub-costal; 6.
A few small families such as the Evaniidae and the Stephanidae are included here, but the vast majority of the group fall into two large families, the Ichneumonidae and the Braconidae, the former distinguished by the presence of two median (or discoidal) cells in the fore-wing (figs.
The placenta is discoidal and deciduate.
The clavicles rest on a large discoidal, rhomb o i d a 1, or T-shaped median bone, which clearly corresponds to the interclavicle of reptiles.
In the Ecaudata the ilium is greatly elongated and the pubis and ischium are flattened, discoidal, and closely applied to their fellows by their inner surfaces; the pelvic girdle looks like a pair of tongs.