3) are among the most remarkable forms. Simple bifid setae, such as those of Oligochaetes, are also present in certain forms.
The setae are either entirely capillary or there are in addition some sigmoid setae even with bifid free extremities.
Shell thin; operculum absent; tentacles bifid; foot secretes a float; pelagic. Janthina.
Cephalic shield bifid posteriorly; margins of foot slightly developed; genital duct diaulic; visceral cornmissure streptoneur ous; shell thick, with prominent spire and elongated aperture; a horny operculum.
The intestinal sac has become bifid and is usually devoid of branches.
They may be characterized as very elongated reptiles without limbs (unless with tiny vestiges of posterior limbs), without eyelids and external ear openings, with the teeth anchylosed to the supporting bones, a bifid slender tongue which is telescoped into its basal half, and with a transverse vent.
Always bifid and re tractile into itself.
The tongue is villose, smooth, bifid anteriorly.
- Teeth solid, almost acrodont; tongue long and narrow, deeply bifid, beset with papillae; no osteoderms; scales of the back very small or quite granular; limbs sometimes reduced.
Tongue long and bifid, with papillae or folds, with osteoderms on the head but not on the body.
The tongue is bifid at the tip in a few genera; usually it is pointed and varies greatly in length, being comparatively short in Andrena, long in the humble-bees(Bombus), and longest in Euglossa, a tropical American genus of solitary bees.
To the right, strobila condition of the scyphistoma, consisting of thirteen metameric segments; the uppermost still possesses the sixteen tentacles of the scyphistoma; the remainder have no tentacles, but are ephyrae, each with eight bifid arms (processes of the disc).
It is of thin membranous consistence, usually obtuse, often bifid, and possesses no central rib or nerve, but has two lateral ones, one on either side; the margins are frequently folded in at the ribs, which thus become placed at the sharp angles.
Among the common characters may be noted the possession of: (i) pectoral mammae; (2) abdominal testes; (3) a bifid apex of the heart; (4) bilophodont molars with a tendency to the formation of an additional lobe from the posterior part of the cingulum.
A characteristic, comparable in value to that presented by the pygidial shield of Arachnida, is the frequent development of a pair of long appendages by the penultimate somite, which with the telson form a trifid, or, when that is small, a bifid termination to the body.