At their opposite ends the dorsal and ventral vessels are probably connected with one another by means of a splanchnic sinus surrounding the stomach.
Didelphia, the alternative name of the group was given in allusion to the circumstance that the uterus has two separate openings; while other features are the inclusion of the openings of the alimentary canal and the urino-genital sinus in a common sphincter muscle, and the position of the scrotum in advance of the penis.
In the light of present knowledge concerning the trade-routes of Asia, which had been in existence for thousands of years ere ever Europeans attempted to make use of them, it is safe to identify Ptolemy's Sinus Perimulicus with the Gulf of Siam, the Sinus Sabaricus with the Straits of Malacca from their southern portals to the Gulf of Martaban, the Aurea Chersonesus with the Malay Peninsula, and the island of Iabadius or Sabadius - the reading of the name is doubtful - with Sumatra, not as has often been mistakenly attempted with Java.
By coalescence of the endoderm-layers, the coelenteron may be reduced to vessels, usually eight in number, opening into a ring-sinus surrounding the pore.
The whole sinus venosus has become part of the right atrium.
There are no lacunar blood spaces with ill-defined or absent walls except for a sinus surrounding the intestine, which is at least frequently present.
The dorsal vessel also communicates with the ventral vessel indirectly by the intestinal sinus, which gives off branches to both the longitudinal trunks, and by tegementary vessels and capillaries which supply the skin and the nephridia.
The difference is that it is broken up into a complex sinus system.
Here also the blood system has no communication with the sinus system of the coelom.
Dorsalwards into the peri - cardial sinus through fine perforations of its floor, and so makes its way into the heart again.
Of the families Belo- stomatidae, Nepidae, Corixidae and Hydrometridae have a pulsating sac at each knee-joint to assist the flow of blood through the legs, while in dragon-flies and locusts (Acridazdae) there is a ventral pulsating dia phragm, which forms the roof of a sinus enclosing the nerve-cords.
(3) The muzzle more or less shortened, the frontal sinus enlarged, and the cranium elevated and diminished in capacity.
Dv, dorsal vessel passing into central sinus (bs).
HADRUMETUM, a town of ancient Africa on the southern extremity of the sinus Neapolitanus (mod.
These spaces are as follows: - (i.) the great arm-sinus; (ii.) the small arm-sinus together with the central sinus and the peri-oesophageal sinus, and in Discinisca and Lingula, and, to a less extent, in Crania, the lip-sinus; (iii.) certain portions of the general body cavity which in Crania are separated off and contain muscles, &c.; (iv.) the cavity of the stalk when such exists.
The great arm-sinus of each side of the lophophore lies beneath the fold or lip which together with the tentacles forms the ciliated groove in which the mouth opens.
These sinuses are completely shut off from all other cavities, they do not open into the main coelomic space nor into the small arm-sinus, nor does the right sinus communicate with the left.
The small arm-sinus runs along the arms of the lophophore at the base of the tentacles, and gives off a blind diverticulum into each of these.
In the region of the mouth where the two halves of the small arm-sinus approach one another they open into a central sinus lying beneath the oesophagus and partly walled in by the two halves of the ventral mesentery.
This sinus is continued round the oesophagus as the peri-oesophageal sinus, and thus the whole complex of the small arm-sinus has the relations of the so-called vascular system of a Sipunculid.
In Discinisca and Lingula there is further a lip-sinus or hollow system of channels which traverses the supporting tissue of the edge of the mantle and contains muscle-fibres.
In Crania, where only indications of the lip-sinus occur, there are two other closed spaces.
The posterior occlusor muscles lie in a special closed space which Blochmann also regards as coelomic. The posterior end of the intestine is similarly surrounded by a closed coelomic space known as the peri-anal sinus in which the rectum lies freely, unsupported by mesenteries.
Small arm-sinus, containing musclefibres.
Interior of dorsal small arm-sinus and, running valve.
The dorsal branch sends a blind twig into each of the diverticula of the dorsal mantle-sinus, the ventral branch supplies the nephridia and neighbouring parts before reaching the ventral lobe of the mantle.
The chief arm-nerve traverses the lophophore, being situated between the great arm-sinus and the base of the lip (figs.
The under arm-nerve, which lies between the small arm-sinus and the surface, supplies nerves to the muscles of both arm-sinuses (figs.
Their minute structure is closely similar in the two cases; the leaf-like plates receive blood from the great sternal sinus, and serve as respiratory organs.
Opening in pairs in each somite, right and left into the pericardial sinus are large veins, which bring the blood respectively from the gill-books and the lungbooks to that chamber, whence it passes by the ostia into the heart.
The blood is brought to the respiratory organs in both cases by a great venous collecting sinus having a ventral median position.
In both animals the wall of the pericardial sinus is connected by vertical muscular bands to the wall of the ventral venous sinus (its lateral expansions around the lung-books in Scorpio) in each somite through which the pericardium passes.
R B A B C must cause a depression of the floor of the pericardium and a rising of the roof of the ventral blood sinus, and a consequent increase of volume and flow of blood to each.
Whether the pericardium and the ventral sinus are made to expand simultaneously or all the movement is made by one only of the surfaces concerned, must depend on conditions of tension.
Another character is the absence of a hollow chamber, or sinus, within the frontal bone of the forehead.
A considerable length of the toga was allowed to hang from the left shoulder; the remainder was passed round the body so as to rise like a baldric (balteus) from the right hip to the left shoulder, being folded over in front (the fold was called sinus), then brought round the back of the neck so that the end fell over the right shoulder; the hanging portion on the left side was drawn up through the sinus, and bulged out in an umbo (Plate, fig.
C, genital sinus and neighbouring parts (from Sommer); a, ventral sucker; b, cirrus sac; c, genital pore; d, evaginated cirrus sac: e, end of vagina; f, vasa deferentia; g, vesicula seminalis; h, ductus ejaculatorius; i, accessory gland.
Built at the head of a gulf, the Sinus Immundus, or Foul Bay, of Strabo, it was sheltered on the north by Ras Benas (Lepte Extrema).
Of Neapolis, on the Sinus Baianus, a bay on the W.
In these the furcal branches are linear or rudimentary, the shell is without rostral sinus, and, besides distinguishing characters of the second 2ntennae, they have always a branchial plate well developed on the first maxillae, which is inconstant in the other tribe.
The pallial line, which is the line of attachment of the mantle parallel to the edge of the shell, is not indented by a sinus at the posterior end.
In the address prefixed to the Arithmetica logarithmica (1625) Briggs bids the reader not to be surprised that these logarithms are different from those published in the Descriptio :- " Ego enim, cum meis auditoribus Londini, publice in Collegio Greshamensi horum doctrinam explicarem; animadverti multo futurum commodius, si Logarithmus sinus totius servaretur o (ut in Canone mirifico), Logarithmus autem partis decimae ejusdem sinus totius, nempe sinus 5 graduum, 44, m.
Istam autem mutationem ita faciendam censebat, ut o esset Logarithmus unitatis, et 10000000000 sinus totius: quod ego longe commodissimum esse non potui non agnoscere.
The lemma is enunciated as follows: " Quaestiones omnes, quae per sinus, tangentes, atque secantes absolvi solent, per solam prosthaphaeresim, id est, per solam additionem, subtractionem, sine laboriosa numerorum multiplicatione divisioneque expedire."
In siphonate forms the pallial muscle is not simple, but is indented posteriorly by a sinus formed by the muscles which retract the siphons.
The blood makes its way by large veins to a venous sinus which lies in the middle line below the heart, having the paired renal organs (nephridia) placed between it and that organ.
Pecten; shell orbicular, with equal auriculae; without a byssal sinus; British.
Chlamys; anterior auricula the larger and with a byssal sinus; British.
With a sinus; freshwater.
Veneridae.-Foot well developed; pallial sinus shallow or absent.