Heider bryonic membranes are vestigial or entirely wanting.
Tail vestigial or absent.
In some Psocidae the wings are in a vestigial state, and the fully winged species rarely if ever fly.
The alimentary canal, which may be represented by a vestigial structure, is accordingly not functional, and the larva does not become pelagic. A pyriform organ is present in most Gymnolaemata as well as the sucker by which fixation is effected.
in the ostrich and in the Amazon parrots, which are vestigial feathers without barbs.
With large crop, vestigial caeca.
The anterior antennae are fused with the anchoring attachment, whilst the posterior pair is vestigial, and the appendages of the mouth and body present various degrees of degeneration and specialization.
o or vestigial hindlimbs.
In the male of Phyllodromia the rudiment of a vestigial ovary becomes separated from the developing testis, indicating perhaps an originally hermaphrodite condition.
Cope (Proc. Ac. Philad., 1864, p. 230) resorted to the modifications of the squamosal, ectoand endopterygoid bones, the condition of the vestigial limbs, and the teeth:- Scolecophidia (Typhlopidae), Catodonta (Glauconiidae), Tortricina (Ilysiidae and' Uropeltidae), Asinea, Proteroglypha and Solenoglypha.
Eyes vestigial or hidden; lower jaw toothless; without enlarged ventral scales: Typhlopidae.
On the other hand, the reduced feelers, the numerous Malpighian tubes (40), the large complex eyes, the vestigial condition of the jaws, the excessive size of the fore-wings as compared with the hind-wings and their complex neuration with an enormous number of crossnervules are all specializations.
17, C, a); he suggests they may represent vestigial structures pointing back to some ancestral form beyond the limits of the present group. The Gnetales probably had a separate origin from the other Gymnosperms; they carry us nearer to the Angiosperms, but we have as yet no satisfactory evidence that they represent a stage in the direct line of Angiospermic evolution.
Finally, there is the hypothesis that marsupials are the descendants of placentals, in which case, as was suggested by its discoverer, the placenta of the bandicoots would be a true vestigial structure.
Maxillulae vestigial or absent.
In the Malacostraca it is absent in the adult, or persists only in a vestigial condition, as in some Decapoda and Schizopoda.
Hallux vestigial or absent since Oligocene.
The extreme of this " division of labour " is seen, in those insects whose jaws are vestigial in the winged state, when, the need for feeding all behind them, they have but to pair, to lay eggs and to die.
Mandibles present in pupa, vestigial in imago; maxillae suctorial without specialization; first maxillae with lacinia, galea and palp. Prothorax small.
Mandibles absent in imago, very exceptionally present in pupa; first maxillae nearly always without laciniae and often without palps, or only with vestigial palps, their galeae elongated and grooved inwardly so as to form a sucking trunk.
But the vestigial jaws, numerous Malpighian tubes, and specialized wings of may-flies forbid us to consider the order as on the whole primitive.
The Corrodentia retain vestigial maxillulae and two pairs of Malpighian tubes, but the wings are somewhat specialized in the Copeognatha and absent in the degraded and parasitic Mallophaga.
It seems likely that the coelomic pore-canals were originally excretory organs, but in the existing Enteropneusta the pore-canals (especially the collar canals) have, as we have seen, acquired new functions or become vestigial, and the function of excretion is now mainly accomplished by a structure peculiar to the Enteropneusta called the glomerulus, a vascular complex placed on either side of the anterior portion of the stomochord, projecting into the proboscis-coelom.
are absent or vestigial in all other insects; and, in most genera, by the presence in the adult of abdominalappendagesused for locomotion, these latter varying in number from one to nine pairs.
Development shows that the glandular tube is mesoblastic in origin and is of the nature of a coelomoduct, while the end-sac is to be regarded as a vestigial portion of the coelom.
It is urged that the imperfect placenta of the bandicoots instead of being vestigial, may be an instance of parallelism, and that in marsupials generally the allantois failed to form a placental connexion.
It is regarded as a modified zooecium, the polypide of which has become vestigial, although it is commonly represented by a sense-organ, bearing tactile hairs, situated on what may be termed the palate.
Biting mandibles; vestigial maxillulae; second maxillae incompletely fused.
Eyes vestigial; teeth restricted to the lower jaw; without en- larged ventral scales: Glauconiidae.
Vestigial palps have been described in various species of Hemiptera, but the true nature of these structures is doubtful.
a, Female from above; d, Jaws, more highly magnified b, From beneath, magnified 5 (tips of mandibles and 1st times; maxillae still more highly c, Vestigial wing; magnified).
In the absence of cerci the Corrodentia are more specialized than the Isoptera and Plecoptera, but some of them show a more primitive character in the retention of vestigial maxillulae - the minute pair of jaws that are found behind the mandibles in the Aptera.
In the parasitic Rhizocephala and in a few Copepoda (Monstrillidae) the alimentary canal is absent or vestigial throughout life.
It has been suggested that the above-mentioned callosities or " chestnuts " on the limbs of horses are vestigial scent-glands; and it is noteworthy that scrapings or shavings from their surface have a powerful attraction for other horses, and are also used by poachers and burglars to keep dogs silent.
The proboscis-pores are highly variable, and frequently only one is present, that on the left side; sometimes the pore-canals of the proboscis unite to open by a common median orifice, and sometimes their communication with the probosciscoelom appears to be occluded, and finally the pore-canals may be quite vestigial.
Although an integral portion of the gut, it has ceased to assist in alimentation, its epithelium undergoes vacuolar differentiation and hypertrophy, and its lumen becomes more or less vestigial.
But in some genera it is greatly reduced and in many quite vestigial.
In the Achorutidae the head is forwardly directed, the tergum of the prothorax conspicuous, and the spring small or vestigial.
All the cephalic appendages are much reduced, the mandibles have no palps, and the maxillulae are vestigial.
Image shows vestigial lower sideband, sound subcarrier at 6MHz above (calibration sort of OK!
Thus the arms are reduced to a single pair and possess no tentacles, there is no definite operculum, and the -alimentary canal is vestigial.
In the Cestodes the vagina is present (V); the canal of Laurer (LC) is now vestigial (present in Caryophyllaeus as the posterior vagina).
The evolution consists first in progressive increase in size; second, in the acceleration of the median digit and retardation of the lateral digits, the latter becoming more and more elevated from the ground until finally in Equus (6) they are the lateral splints, which in the embryonic condition have vestigial cartilages attached representing the last traces of the lateral phalanges.
3a) shows an interesting vestigial condition of the wings, which are but poorly developed in the male (fig.
8) and Cumacea (or Sympoda), however, leads to the conclusion that the coalescence of the first thoracic somite with the cephalon really involves a vestigial shell-fold, and, indeed, traces of this are said to be observed in the embryonic development of some Isopoda.
Image shows vestigial lower sideband, sound subcarrier at 6MHz above (calibration sort of OK !
Whether it is some vestigial part of primate clan and tribe definition, or early warning system of predatory approach, or mating ritual, I don't know.
Hallux absent or vestigial.
Spinae sterni vestigial.
The feelers are branched and the jaws vestigial.
Wings absent or vestigial.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.