The dorsal surface is positive, the ventral negative, and the discharge of a large torpedo is sufficient to temporarily disable a man; yet it is not so powerful as that from a big electric eel.
The powerful caudal fin is the principal agent in swimming, aided by undulatory movements of the dorsal and ventral fins; and it has a twisting action that drives the animal forward as does the rolling of the oar in "sculling" a boat.
Within the shell the body is enveloped in a "mantle," or fleshy membrane falling like a cloak on each side; and from it is secreted the outer shell, which grows by additions to its ventral margin.
Vertebrates are bilaterally symmetrical animals, with an internal skeleton, the axis of which is composed of similar segments (vertebrae) and divides the body into a dorsal and a ventral portion.
The stomach, liver, and other viscera, lie in the ventral part of the body.
There is a well-developed ventral foot, on which the animal creeps, and in front of it a distinct head bearing eyes and tentacles.
Restoration of the ventral surface, based upon the photographs and descriptions published by Walcott.
The ventralside of the specimen described by Mickleborough and now in the U.
The test is in solid black and the part within the ventral membrane dotted.
In the Utica black shales, near Rome, New York, there was finally discovered in 1892 a layer less than ten millimeters thick, bearing hundreds of Triarthrus becki with most of the ventral anatomy intact.
These arches appear as flat bands separated by a thin connecting membrane, somewhat as the arches in the ventral surface of some of the Macrouran Decapods.
Ventral side of the pygidium and greater part of the thorax of an individual of medium size.
If, therefore, this depends upon the secondary ventral deflection of the oral region, as seems to be the case, then it is a priori probable that the anterior part of the canal has also shared in this ventral inflection.
The dorsal surface of the pterygoid is rounded anteriorly and somewhat flattened posteriorly, whereas the ventral surface is gently rounded along its length, except that there is a high median crest.
Dark stripes either absent posterior to the nape, or present as a row of small spots on fourth or seventh scale-row; no dark stripe on first scale-row; eight supralabials having dark ventral margins.
In this group the color pattern is characterized by the high frequency of ventral spotting, darkening of part of the supralabials, dark pigmentation on the 1st scale-row, and more than four dark stripes on the body of adults.
The palatine teeth are set in shallow sockets on the ventral edge of the bone.
Posterior to the splenial and also forming a part of the ventral surface of the mandible is the wedge-shaped angular, which lies directly beneath the fused surangular-prearticular.
The maxillary teeth are set in sockets on the ventralsurface of the bone.
The ventral part of the insertion is fleshy in one leg.
Presumably these represent the primitive dorsal extensor and ventral flexor muscle masses.
The muscle arises fleshily from the posterior end of the anterior iliac crest (ventral to the origins of Mm.
Likewise he used the term flexor to indicate derivation from the primitive ventral flexor muscle mass.
Posterior view of the left tarsometatarsus, showing the ventral intrinsic muscles of the foot.
The ventral ramus of S2 divides into two branches, only the posterior of which contributes to the plexus; the anterior branch directly innervates muscles of the abdominal wall (as does the entire ventral ramus of S1).
The entireventral ramus of each of these nerves, excepting S2 and S9, contributes to this plexus.
The muscle attaches to the proximal end of the subarticular cartilage ventral to the trochlea for digit III.
Pars ventralis: The attachment is fleshy and tendinous to the ventral edge and the deep surface of the tendon of pars postica.
A glass slide one millimeter thick was placed on the ventral side of the skull.
The mid-ventral white stripe characteristic of pullus is present in three of 28 adults from El Salvador.
Illustration: PLATE 3 Photographs of skulls inventral view of Baiomys.
The distance from the dorsalmost part of the braincase to a flat plane touching tips of incisors and ventral border of each auditory bulla.
Illustration: PLATE 4 Photographs of skulls in ventral view of Baiomys.
The collecting brushes are either on the hind legs or, as in some cases, on the ventral surface of the body.
When its fit of terror was over, however, it became still, and would allow me to push it hither and thither, merely waving the edges of its dorsal and ventral fins rapidly as it yielded to the impulse.
Figure shewing the accessory genital gland of male, which opens on the last pair of legs by a papilla on the ventral side.
The figure represents the Wolffian ducts (wd) with ventral portion removed so as to expose their inner surface, and shews the junction of the two W.
The section is mainly intended to illustrate the formation of the ventral wall of the alimentary canal from cells formed around the nuclei of the yolk.
The dissection is viewed from the ventral side, and the lips, L.
Transverse section through the ventral part of the trunk of an embryo Scyllium of stage P, in the region of the pelvic fin, on the same scale as fig.
The last left (17th) leg of a male Peripatus capensis, viewed from the ventral side to shew the papilla at the apex of which the accessory gland of the male, or enlarged crural gland, opens to the exterior.
The formation of the body-cavity in the muscle-plate and the ventral thickening of the parietal plate.
Portion of ventralcord of Peripatus capensis enlarged, shewing two ganglionic enlargements and the origin of the nerves and commissures.
A left leg of Peripatus capensis, viewed from theventral surface; x 30.
Ganglionic enlargement on ventral nerve-cord, from which a pair of nerves to foot pass off.
Cells formed around the nuclei of the yolk to enter into the ventral wall of the alimentary canal.
Transverse section through the ventral part of the trunk of an embryo Scyllium of stage P, in the region of the pectoral fins, to shew how the fins are attached to the body, magnified 18 diameters.
If the collecting bee is seized with forceps and examined after it has crawled over the stamens of a few flowers of the corn, its legs and the ventral surface of its body are found to be thickly powdered over with pollen.
The second pair of legs remove scattered pollen from the thorax, more particularly from the ventral region, and they received the pollen that has been collected by the first pair of legs.
All of the legs receive a supply of this free pollen and much adheres to the hairs which cover the body, more particularly to those upon the ventral surface.
In Thrinaxodon the dorsal and ventral postorbital processes, arising from the postorbital and jugal bones respectively, nearly meet but remain separate.
This may merely be a device to provide great dorsal-ventral stiffness to the long jaw, but it is possible and probable that some part of the temporal muscle was inserted on the inner surface of the coronoid.
The ventral margin of this part of the ramus curves dorsally in a gentle arc that terminates posteriorly at the base of the retroarticular process.
However, the area of insertion lies mostly ventral to the articulating surface of the articular bone and extends but slightly in front of it.
The anterior pterygoid extended obliquely backward and downward from its origin, passed medial to the temporal muscle and inserted on the ventral and medial surfaces of the splenial and angular bones beneath the Meckelian fossa.
Consequently, the masseter was able to extend from an anterodorsal origin to a posterior and ventral insertion.
The masseter probably arose from the quadratojugal, the jugal, and ventral parts of the squamosal, although scars on the quadratojugal and jugal are lacking.
STER'NITE, the ventral portion of the somite of an arthropod.
Brachiopods, from the form of the ventral valve of their shell termed Lamp-shells.
No pregnancy existed, but there was found a ventral hernia of the abdominal viscera through an opening which extended the entire length of the linea alba, and which was four inches wide in the middle of the abdomen.
Atlee submits quite a remarkable case of congenital ventral gestation, the subject being a girl of six, who recovered after the discharge of the fetal mass from the abdomen.
The woman subsequently enjoyed excellent health and, although she had a small ventral hernia, bore and nursed two children.
The abdomen was bound up, and in six weeks the woman was enabled to superintend her domestic affairs; excepting a ventral hernia she had no bad after-results.
The patient speedily recovered, and was discharged in a little over a month, the only disastrous result of his extraordinary injuries being a smallventral hernia.
Upon the ventral surface of each of the rings thus sketched out, a pair of bud-like prominences made their appearance--the rudiments of the appendages of the ring.
And here you have the hinder limbs restored in the shape of these ventral fins.
It had a dorsal fin with 14 spines; a ventral fin; a tail, 16 spines; and in addition to these it had four pectoral fins resembling the claws of a frog, which it used much in the same manner that a lizard uses its claws.
Cephalic foramen: the posterior or occipital foramen of head through which the dorsal vessel, oesophagus, salivary ducts and ventral nerve cords pass from head to prothorax.
Ganglion -ia: a nerve centre composed of a cell mass and fibres: the white disc-like bodies connected by a double cord, lying above the ventral surface within the body and forming the centre of the nervous system.
Dorsal scale: that part of the covering scale of the Diaspinae that lies above the insect, as opposed to the ventral scale, which lies below.
Egg-guide: Orthoptera; two small pointed prolongations of the ventral portion of the 8th abdominal segment, between upper and lower valves, used in oviposition.
Elytral ligula: a tongue-like process on the inner face of the side margin of elytra, to perfect the union with the ventral segments: e.
Collembola: an ordinal term applied to species which are apterous; have no metamorphoses; have variably developed abdominal saltatorial appendages and a peculiar ventral tube at base: the spring-tails.
Gonapophyses: three pairs of processes in the Orthoptera, one arising from the eighth and two from the ninth abdominal segment op the ventral surface.
Epigastrium: the first entire ventral sclerite of the abdomen.
Until recently it was regarded as a general rule that, by the partial segmentation of the vitellus a germinal disc was formed, and in this, corresponding to the ventral surface of the embryo, a primitive band.
The caudal appendages sprout forth like other limbs freely on the ventral surface, whilst in other Prawns, the Porcellanae, etc.
The supposition that certain Cirripedes might once upon a time have selected the soft ventral surface of a Crab, Porcellana or Pagurus, for its dwelling-place, has certainly nothing improbable about it.
In this division the ovipositor issues from the ventral surface of the abdomen; the pronotum reaches back to the tegulae; the trochanter has two segments; the fore-wing (fig.
Ashmead proposes to separate the Agriotypidae (which are remarkable for their aquatic habit, being parasitic on caddis-worms) from the Ichneumonidae on account of their firm ventral abdominal segments and spined scutellum.
The ventral line is the same for some inches behind the anus.
Three of 28 specimens from El Salvador possess the mid-ventral white stripe.
A dorsal and a ventral plate are often distinguished, known respectively as the tergum and the sternum, and the tergum may overhang the insertion of the limb on each side as a free plate called the pleuron.
Lepidurus Angassi: a, dorsal aspect; b, ventral aspect of head showing the labrum and mouth-parts.
The appendages posterior to the mandibles appear as buds on the ventral surface of the somites, and in the most primitive cases they become differentiated, like the somites which bear them, in regular order from before backwards.
The nervous system consists, as in the Worms, of two ganglionic ventral chords.
In the Lampreys there are neither thoracic norventral fins.
In the Mollusca the branchial vessels unite to form laminæ upon the ventral sides, and are already surrounded by a kind of thoracic cavity, the mantle, as is exemplified in the tectibranchiate Gasteropods.
The back holds the same relation to the ventral side as light does to the darkness, as sun to the earth; therefore the dorsal side is of a dark, the ventral of a faint or pale colour.
It forms two ganglionic cords running along the ventral side of the body, and, where it makes with the nerves going to the maxillæ a ring around the pharynx, corresponds to the pharyngeal or pneumogastric nerves.
In the Snails the ventralsurface first becomes a creeping sole.
What is regarded as the dorsal side of the animal is its ventral side, because upon the former lies the pallial aperture and the anus, while the vitelline sac is also inserted there.
They have a double nervous cord upon the ventral surface of the body.
Unlike modern amphibians, with their slimy skin, the Carboniferous amphibians wore an armor of bony scales over the ventral surface and sometimes over the back as well.
If the pod be examined before it bursts, it will be found that the valves are composed of a fleshy substance, lined with a strong membrane or skin, and that they are united by two seams, called the dorsal and ventral sutures.
A genus of Brachiopoda, so called in allusion to the perforated beak of the ventral valve.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "ventral" in a variety of sentences. We hope that you will now be able to make sentences using this word.
