sinus 
Longitudinal sinus, either of two sinuses of the dura 
mater, respectively occupying the upper anil under mar- 
gins of the falx cerebri. The superior begins at the fora- 
men csecuin, and terminates posteriorly at the torcular 
Herophili ; it is lodged in the superior longitudinal groove 
of the cranial vault. The inferior is contained in the in- 
ferior or free margin of the falx cerebri, terminating in the 
straight sinus posteriorly. Also called falciform sinus. 
Ophthalmic sinus. Same as cavernous sinus. Petrosal 
orpetrous sinus. Sec petrosal. Petrosquamous sinus. 
Seei)c(ro.(/Hn)nozis. Placental sinus, the venouschannel 
around the placenta, arising from the free anastomoses of 
veins. Portal sinus, the sinus of the portal vein. See 
below. Prostatic sinus. See prostatic. Pulmonary 
sinuses, the sinuses of Valsalva in the pulmonary artery. 
Rhomboidal sinus, (a) The fourth ventricle. (6) The 
rhomboccelia. Also called sinus rhombmdalis. Sagittal 
sinus, the superior longitudinal sinus. Sinus circularis 
iridis. Same ascanalofSchlemmfyrhich see, undercanad). 
Sinuses Of Cuvier, veins or venous channels of the fe- 
tus, ultimately transformed into the right and left superior 
vena? cavro. Sinuses of the dura mater, channels for 
the passage of venous blood, formed by the separation of 
the two layers of the dura mater, and lined with a con- 
tinuation of the internal coat of the veins. They are 
specified as the superior and inferior longitudinal, 
straight, lateral, occipital, cavernous, circular, superior 
and inferior petrosal, and transverse. Sinuses Of veins, 
pouch-like dilatations of the venous walls on the cardiac 
side of the valves, which produce knot-like swellings when 
distended. Sinus-ganglion, a group of nerve-cells about 
the junction of the venous sinus and the auricle of the 
heart. In the frog the sinus-ganglion, or ganglion of 
Remak, is the collection of groups of nerve-cells on the 
venous sinus. Sinus genltalls. Same as prostatic vesi- 
cle (which see, under prostatic). Sinus of conjunctiva, 
the space between the ocular and palpebral conjunctive. 
Sinus of Highmore, the antrum of Highmore. See 
antrum. Sinus of Morgagni, a space at the upper 
and back part of the superior constrictor of the pharynx, 
just under the base of the skull, where the muscular fibers 
of the constrictor are deficient, the pharynx being conse- 
quently walled in behind by its own aponeurosis. Here 
the Eustachian tube opens into the pharynx on each 
side, and the levator and tensor palati muscles may be ex- 
posed by dissection. Sinus Of the auricle. Same as 
sinus venosus. Sinus of the heart, the principal or main 
cavity of either auricle. Sinus of the Jugular vein, the 
dilatation at the origin of the internal jugular vein just 
outside of the jugular foramen at the base of the skull. 
Sinus of the kidney, the concavity or reentrance at the 
hilum of the kidney. Sinus of the larynx, the ventricle 
of the larynx, leading into the sacculus laryngis, or ctucal 
laryngeal pouch. Sinus Of the portal vein, the en- 
largement of the portal vein just before it divides into its 
two branches for the liver. Also called portal sinus. 
Sinus Of Valsalva, any one of three ponchings of the 
aorta and of the pulmonary artery opposite the segments of 
thesemilunarvalves. Also called mlvularsimu, and respec- 
tively aortic and pulmonary sinus. Sinus pleurae, the re- 
cesses where one layer of the parietal pleura is folded over 
to become another. Sinus pocularis. Same as prostatic 
vesicle (which see, under prostatic). Sinus prostaticus. 
Same as prostatic sinus. See prostatic. Sinus rectus. 
Same as straight simis. Sinus rhomboidalis. Same 
as rhomboidal sinus (which see, above). Sinus tentorii. 
Same as straight sinus. Sinus venosus, in human and al- 
lied hearts, the main part of the cavity of either the right 
or the left auricle of the heart; that part into which the 
veins pour their blood, as distinguished from the auricular 
appendix. Also called atrium, and sinus of the auricle. 
Sinus venosus corneas, Schlemm's canal. Sphenoidal 
Sinuses, cavities in the sphenoid bone, like those of the 
ethmoid and frontal. Straight Sinus, the venous chan- 
nel at the junction of the falx cerebri with the tentorium, 
passing from the termination of the inferior longitudinal 
sinus to the torcular Herophili. Tarsal sinus, the large 
irregular passage between the astragalus and the calca- 
ncuin, occupied by the intertarsal ligament. Transverse 
sinus, a venous network excavated in the dura mater over 
the basilar process, opening into the inferior petrosal sinus 
on each side, and into the inferior spinal veins below. Also 
called basilar sinus, basilar plexus. Urogenital sinus, 
the cavity in which the urogenital organs terminate in the 
fetal life of man and most mammals ; a permanent com- 
partment of the cloaca in many lower vertebrates. See 
cloaca, 3 (a), and urogenital. Uterine sinuses, greatly 
enlarged veins of the womb during pregnancy. Valvu- 
lar sinus. Same as sinus of Valsalva. Venous sinus, 
any sinus conveying venous blood ; especially (a) one of 
the sinuses of the dura mater (see above), or (6) a sinus 
venosus (see above). 
Sinusoid (si'nus-oid), n. 
curve of sines, in 
which the abscissas 
are proportional to 
an angle, and the 
ordinates to its 
sine. 
Sinusoidal (sl-nu-soi'dal), a. [< sinusoid + 
-?.] Of or pertaining to the sinusoid Sinu- 
soidal function. See function. Sinusoidal map-pro- 
jection. See projection. 
Sinusoidally (si-nu-soi'dal-i), adv. In a sinu- 
soidal manner; in the manner of a sinusoid. 
P/iilos. Mat/., XXVI. 373. 
sin-worn (sin' worn), . Worn by sin. [Bare.] 
I would not soil these pure ambrosial weeds 
With the rank vapours of this sin-worn mould. 
Milton, Comus, 1. 17. 
siogun, n. Same as shogun. 
siont, n. An obsolete form of scion. 
-Sion. See -tion. 
Sionite (si'on-It), . [< Siou (see def.) + -ite%.] 
One of a Norwegian body of the eighteenth cen- 
tury, professing the power of prophecy and 
proclaiming the immediate coming of the mil- 
[< sinus + -aid.] The 
5652 
leunium. Ho called from their claim to be con- 
sidered children of the King of Siou. 
Siouan (so'an), a. [< Sioux + -an.'] Pertain- 
ing to the Sioux or Dakotas; Dakotan. 
The Siouan group [of Indians] had its habitat on the 
prairies between the -Mississippi and Missouri. 
Amer. Xat., XXIII. 75. 
Sioux (so), H. and a. [F. spelling of the Ind. 
name.] I. . ; pi. Sioux (so 1 or soz). A member 
of a family of North American Indians, now con- 
fined chiefly to North Dakota, South Dakota, 
andparts of Wyoming, Nebraska, and Montana. 
II. a. Of or pertaining to the Sioux ; Siouan; 
Dakotan : as, tne Sioux wars ; a Sioux village. 
sip (sip), v. ; pret. and pp. sipped, ppr. sipping. 
[< ME. sippen, syppen, < AS. *syppan (not 
found) (cf. 'sypian, sipian, soak, macerate: see 
sipe) (= MD. sippen, sip, taste with the tip of 
the tongue (cf. D. sipperlippen, taste with the 
tip of the tongue), = LG. sippen, sip); a sec- 
ondary form of siipan, sup, taste: seespi. The 
form sip is related to sup (AS. supan) much as 
slip is related to similar forms (AS. sliipan, 
etc.).] I. trans. 1. To drink little by little; 
take (a liquid) into the mouth in small quanti- 
ties ; imbibe a mouthful at a time. 
A woman moved is like a fountain troubled, 
Muddy, ill-seeming, thick, bereft of beauty; 
And while it is so, none so dry or thirsty 
Will deign to sip or touch one drop of it. 
Shalr., T. of the S., v. 2. 145. 
To sip a glass of wine was considered effeminate, and a 
guest was thought ill of if he did not empty his glass at a 
draught. Fortnightly Rev., N. S. , X1III. 377. 
2. To take in gradually by some process analo- 
gous to drinking; receive or obtain by sucking, 
inhaling, absorbing, or the like. 
Where I may sit and rightly spell 
Of every star that heaven doth shew, 
And every herb that sips the dew. 
Milton, II Penseroso, 1. 172. 
3. To drink from by sips. 
They skim the floods, and sip the purple flowers. 
Dryden, tr. of Virgil's Georgics, iv. 76. 
II. intrans. To take a sip or sips. 
They could never get her so much as sip on a cup with 
the proudest of tjieni all. Shak., M. W. of W., ii. 2. 77. 
Modest as the maid that rips alone. 
Pope, Dunciad, iii. 144. 
Sip (sip), 11. [< ME. sippe ; <sip,r.] 1. The 
act of sipping, or drinking by small quantities, 
as a liquid. 
"Here 's wussing health to ye, Robin " (a sip), "and to 
your weelfare here and hereafter " (another taste). 
Scott, Rob Roy, xxxiv. 
2. A very small draught ; a taste (of a liquid). 
One sip of this 
Will bathe the drooping spirits in delight 
Beyond the bliss of dreams. Milton, Comus, 1. 811. 
3f. Drink; sup. 
Thus serveth he withouten mete or sippe. 
Chaucer, Anelida and Arcite. 1. 193. 
sipage (si'paj), w. [< sipe + -age.] Same as 
seepage. 
sipahee, n. Same as sepoy. 
sipahselar (si-pa'se-lar), n. [Hind., < Pers. 
sipdli-salar, army-leader.] In India, a com- 
mander-in-chief ; a commanding general : as, 
the sipahselar Timour. 
sipe (sip), r. i. ; pret. and pp. siped, ppr. siping. 
[Also seep (also spelled seip, sepe) ; < ME. *sipen, 
< AS. *sypian, sipian, soak, macerate ; cf. AS. 
"sipan (pret. sap, pp. "sipen), drop, trickle (cf. 
sipenige, MD. sijpooghe, sijpooghig, with run- 
ning eyes), = OFries. *sipa (in comp. pp. bi- 
sepen, bi-seppen) = MD. sijpen, D. sijpen, drop, 
= LG. sipen, ooze, trickle (freq. sipern = Sw. 
sippra, ooze, drop, trickle); appar. not an orig. 
strong verb, but related to sipian, etc., and ult. 
< siipan, sup, taste : see sip, sup. Cf. seep.] 1. 
To ooze; trickle; soak through or out. 
The siping through of the waters into the house. 
Granger, On Ecclesiastes (1621), p. 316. (Latham.) 
Her throat's sair misguggled, . . . though she wears 
her corpse-sheet drawn weel up to hide it, but that can- 
na hinder the bluid seiping through. 
Scott, Heart of Mid-Lothian, xvii. 
2. To steep; soak. 
The leaves [of the mullen] are boiled in fresh cow's 
milk, and, after boiling a moment, the infusion is allowed 
to stand and sipe for ten minutes, when it is strained, 
sweetened, and drank while warm. 
New York Tribune, Sept. 6, 1886. 
[Prov. Eng., Scotch, and U. S. in both uses.] 
siphert, . An obsolete form of cipher. 
sipMlis, n. See syphilis. 
Siphneinae (sif-ne-i'ne), n . pi. [NL., < Siphneus + 
-inss.] A subfamily of Muriilse, typified by the 
genus Sipltnetis, containing mole-like murine 
siphon 
rodents with rudimentary external ears and 
short limbs and tail. The group combines some 
characters of the A frimliuic (which are 
with others of the different family 
siphneine (sif'ne-in), a. Of the character of 
the (Uphneinee, or belonging to that subfamily. 
Siphneus (sif'ne-us), n. [NL. (Brants, 1827), 
< Gr. aipvei's, a mole.] 1. The typical genus of 
>/i neinee. S. armanrli is a Tibetan species with 
large fossorial fore feet and a mole-like aspect. 
2t. A genus of reptiles. Fitzimjer, 1843. 
siphon (si'fon), n. [Also syphon ; < F. xij>lii>n 
= Sp. fiifoii = Pg. siphSo = It. xij'one, < L. si- 
pho(ti-), perhaps < Gr. oifav, a tube, pipe, 
siphon; akin to oi<l>'/-6<;, hollow.] 1. A bent 
pipe or tube with 
legs of unequal 
length, used for 
drawing liquid out 
of a vessel by caus- 
ing it to rise in the 
tube over the rim 
or top. For this pur- 
pose the shorter leg is 
Inserted in the liquid, 
and the air is exhaust- 
ed by being drawn 
through the longer 
leg. The liquid then 
rises by the pressure 
of the atmosphere and fills the tube, and the flow 
begins from the lower end. Sometimes an ex- 
hausting-tube (a in the figure) is placed on the longer 
leg; the air, in that case, is sucked out through a till the 
tube Is filled to the cock b, which is then opened, and the 
flow commences the cock b being so constructed as to 
close the suction-tube when the siphon is running. But 
the more general method is to fill the tube in the first 
place wiih the liquid, and then, stopping the mouth of 
the longer leg, to insert the shorter leg in the vessel ; 
upon removal of the stop, the liquid will immediately begin 
to run. The flow depends upon the difference in vertical 
height of the two columns of the liquid, measured re- 
spectively from the bend of the tube to the level of the 
water In the vessel and to the open end of the tube. The 
flow ceases as soon as, by the lowering of the level in the 
vessel, these columns become of equal height, or when 
this level descends to the end of the shorter leg. The 
atmospheric pressure is essential to support the column 
of liquid from the vessel up to the top of the bend of the 
tube, and this height is consequently limited, varying in- 
versely with the density of the liquid. At sea-level the 
maximum height is a little less than 30 inches for mercury 
and 34 feet for water. 
2. In zool., a canal or conduit, without refer- 
ence to size, shape, or function; generally, a 
tube or tubular organ through which water or 
other fluid passes ; a siphuncle. specifically (a) 
In Mollusca: (1) A tubular fold or prolongation of the 
mantle, forming a tube, generally paired, capable of pro- 
traction and retraction, characteristic of the siphonate or 
sinupalliate bivalves. It conveys water, and is of vari- 
ous shape and size, sometimes several times longer than 
the rest of the animal when fully extended, but usually 
capable of being withdrawn into the shell. In Teredo 
the united siphons are so long that the mollusk resem- 
bles a worm. See cuts under ship-worm, Teredo, quahog, 
and Jfj/ai. (2) A similar siphon in some gastropods, ex- 
tending from the anterior portion of the mantle over the 
head. See cut under Siphonostomata, 2. (3) The charac- 
teristic siphuncle, funnel, or infundibulum of cephalo- 
pods, formed from the mesopodium, and serving as an 
organ of locomotion by confining and directing the jet 
of water which is forced through it. See siphuncle. (4) 
A tubular or canaliculate formation of the shell of any 
tnollusk which covers or protects the soft siphon ; espe- 
cially, the siphuncle of a cephalopod, or the communi- 
cation between the compartments of the shell. (6) In 
Rotifera, the calcar or tentaculum, a part or process of 
the trochal disk, supposed to be a sense-organ, (c) In 
Protozoa, one of the tubes which traverse the septa of the 
interior of polythalamous tests, as the shells of foramini- 
fers. (d) In entom., the suctorial mouth-parts or suck- 
ing-tube of some insects, as fleas (Siphonaptera) and bugs 
(Siphoiiata). (e) In Crustacea, the suctorial mouth-parts 
of various parasitic forms. See Siphonostomata, 1. (/) In 
Vermes, a spout-like process of the mouth of gephyrean or 
sipunculacean worms. See Gephyrea and Sipunculoidea. 
(g) In Echinodermata, a tubular formation connected with 
the alimentary canal of some sea-urchins. 
3. leap.] [NL.] IncoHC/f^agenusofgastropods. 
Also Sipho (Klein, 1753; Fabricim, 1822) and Sy- 
pho (Brown, 1827). 4. In not., one of the small 
peculiar cells surrounding the large elongated 
central cell in the frond of certain florideous 
algee. See monosiphonons, polysipJ/onotis, I'oly- 
siphonia, pericentral. 5. A siphon-bottle. 
Automatic siphon, a siphon which is set in operation by 
an alternate vertical movement, by which means the liquid 
is forced little by little to the necessary height through a 
valve in the short arm. Siphon-filling apparatus, an 
apparatus for filling siphon-bottles with aerated liquids. 
It holds the bottle, and by means of a lever opens the valve 
and permits the liquid to enter. It is usually provided 
with a screen to protect the operator from injury in case 
the bottle bursts. Siphon-hinge cartilage. See carti- 
lage. Wurtemberg siphon (so called from its having 
been first used in that country), a siphon with both legs 
equal, and turned up at the extremities. 
siphon (si'fon), r. [(.siplion, n.] I. trans. To 
convey, as water, by means of a siphon ; trans- 
mit or remove by a siphon, 
