;
haat

Lagat

oe ay
ee ee

iy A
lees
hae! te

PROCEEDINGS

OF THE

WASHINGTON ACADEMY OF SCIENCES

VoL. VII, pp. 27-157. Piates I-VI. JUNE 20, 1905.

THE BLOOD-VASCULAR SYSTEM OF THE LOR-

SECTION

I.
lille

Ill.

SECTION

Wie
VI.

Vil.

VIII.
IX.
X.
exalts
XII.
XIII.

ICATI, THE MAIL-CHEEKED FISHES.

By WIiLuiaAm F. ALLEN.

CONTENTS.

PAGE
Wi—- Cr OMUCLOFY) ofa ts ot STU NC INS KRIS Soar aCe eis Nos take 11S)
Introd GhiOmye arent Suhr at erasers Ae Cade hel a) ste Aete e r Samet mn
(NEC TNCNEE:: BPA ioe ClOk PR BAA he te noe etre adty Care Ms pet ho baste 30
Lee UEC Se VAS SCEte noik et esd cis et -eitay seas agleul ariel a Toy coubret ls 30
Dis PXPDPENMENAB ES Sey, Se ae IE IOP CCRCEN Ee WORC IRE MOM OMe) Nau iD! 16: Uc 31
aoe lode OfperOCedUnew an. st rteculdctes) i tctuel co: (clecibal imines 31
TLIStOTICAP RE VIGWE ae oso)" Pret tad oy rela ot aoron ia) ln 8) sahct ah ieniok ont. 3
VRB Car ene a cyt San Sry aed ae Mic Rey Ow ph oe ae Voll od for) ote ee ad te 36
General Survey of the Blood Vessels in Ophiodon. ...... 36
leant Pen aera n ty eoreagi at oi Ganka Th sca es Pec cae ll ae 38
Benipheral Distributions Of the -Anteniesrs <0r..'.8 a /iicn ce) bettas 43
I. Branchial Arteries .. . Bric esd LE IE Red BA eee 43

2. Arteries Arising from the Ventral Ends of the Bierent
branchial Artericswrst soc) oe ata ls may eure Mette ed an 46
eC AE OCH ELECEICSET On Ge haw ke Abia: ven (A) cay) os ett oh) ah tan vee ate 51
4. Opercular and Dorsal Branchial Muscle Arteries . .... 62
5. Subclavian Arteries eee An OA al Wes tet Ran EN cal a 63
G2 Conlizeo-Mesentente, Arteryy .)e¥ as 5) shoe el es auley o bolle 65
PP WOUSAENGKtAN AM aR Mam Mei ay fat tohe ey vals doe Syl hel becela | a eearetediee 73
perineal Distribution of the Veins Pay art av kt at atrad a Metts 78
Thy US aC SMrm ee em Hiern suru be Oak ow dicot otal en Rawle 78

2. Vessels Emptying Directly into the Jugular or into the Head
GOED 5 Gh ge Pe Une pat Bere PMI BaP OOM rn nS ell 87
Fa MMceniomy \acmlae WEInSy apse. ey oh!) hee a ac A? uh sp bo Mayuomneae gI
ARB VICILCR AME VICI Sieger ki Aik aie cor ah ali ay loess (fh Lan! utc) a home akin omks 93
ig ENG Lea ATO A OTELSY clita) aM hv ahr aor oral! afta) ‘ey aye, ays eien aieas 94
Gy Elepaties Pontah System sas (aiid 6) e.g oo), S apenoge 96
Te eriabeb Orta SVStOTig sys. de- su wl Ya a) o) 22y),at), tsb gene ane 106
Wascalan system im Amoplopoma .) 2.2?) 4)')\ 2) san ee ats 113
Generali Considerations and) Summary. ..)4)<)s a1) eos = 120
Brief, Synonymy of the, Blood Vessels):))./) iis va) aes alee ie 125
Bibliographivarae ste ah serep ssh cette tye. os iam Lenn et oi eel clase in 132
Explanation: om the Platesy 03) sjas0e. sate: ET EL NES TE NIA 138

Reference Letters and Abbreviations Used in the Figures. . . 149

28 ALLEN

SECTION I. INTRODUCTORY.

I. INTRODUCTION.

Tue blood-vascular system of fishes is no new subject. It
has been carefully worked out for many groups. We have the
memoirs of Miiller on Myxcne, T. J. Parker on JZlustelus,
Hyrtl on the roaches, McKenzie on Ameiurus, Vogt on
Salmo, Emery on fierasfer, Cuvier and Valenciennes on
Perca, and the general account found in Stannius’ Anatomy.
The object of this paper is to give a fairly complete account of
the vascular system of Ophiodon elongatus (blue cod); and to
make some comparisons with other members of the suborder
LORICATI, the mailed-cheeked fishes. In a later paper I
hope to go more into detail with the peripheral endings of the
vessels in the organs of the viscera and those of special sense,
as well as to take up the lymphatics.

This group of fishes is distinguished by the extension of the
third suborbital bone across the cheek as a stay to or toward
the preopercle. In view of the wide variation in this group,
Dr. Gill says (45)' that it is not a natural division. He, how-
ever, divides this suborder into 8 different families, placing the
Scorpenide (the rock fishes), as the most generalized, on
account of their resemblance in form to the Serranide and
Sparide ; and the Cottidz (the sculpins) are placed as the most
specialized. Between these extremes come the family Hexa-
srammide, placed nearer the Scorpznide than the Cottide.
There are, however, many points of resemblance to the Cottidz
to be found in their osteology, visceral organs, nervous and
vascular systems.

The subfamilies Hexagrammine, Ophtodontine, Zaniolepr-
dine, and Oxylebiine, given by Jordan and Evermann (45, p.
1864), are very strongly marked. Ophzodon and probably
Zantolepis are about as closely related to Scorpenzchihys, a
sculpin, as they are to Hexagrammos, and should be regarded
as types of distinct families.

The following species of fishes were studied.

1 All figures in brackets refer to bibliography at the end of the paper.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 29

Family ScoRPANIDA.

Sebastodes flavidus Ayres, yellow-tail rockcod; S. melanops
Girard; S. mystinus J. & G., black fish; S. aurzculatus
Girard, brown rockcod; S. carnatus J. & G., flesh-colored
rockcod, and S. zedulosus Ayres, yellow-spotted rockcod.

Family ANOPLOPOMATIDZ.

Anoplopoma fimbria Pallas, black cod.

Family HEXAGRAMMID.

Hexagrammos decagrammus Pallas, sea trout and Ophzodon
elongatus Girard, blue cod.

Family CoTrTip.

Scorpenichthys marmoratus Ayres, cabezon ; Calycilepidotus
spinosus Ayres, and Hnophrys bison Girard.

For detailed work, Ophzodon eclongatus was taken as a type.
The reason for choosing Ophzodon was partly because of its
position between the 2 extremes of the suborder, but espe-
cially on account of its size (sometimes reaching a weight of
70 lbs.), and the ease with which it can be injected. Every
effort has been made toward accuracy. Several specimens of
each species compared have been studied, in order to eliminate
the error that might come from variation in different individuals
of the same species. Notwithstanding, omissions, if not errors,
have probably crept in. The drawings, rude as they may be,
were all made from a single dissection, with the exception of
Pl. I, fig. 1, which is a combination of several dissections.

The material for this paper was collected by Chinese fisher-
men at Monterey Bay, Cal. The work was done at Stanford
University and at the Hopkins Seaside Laboratory, and under
the direction of Prof. C. H. Gilbert, to whom I am indebted
for many favors and the facilities for research. Also I am
under the greatest obligations to Prof. G. C. Price, of Stanford
University, for a room at the Hopkins Laboratory; and to Mr.
J. C. Brown of the University of Minnesota, for-many favors.

30 ALLEN

II. TECHNIQUE.

1. Injecting Masses.

Nearly every injecting mass and color has been tried, but the
most satisfactory, as well as the cheapest, proved to be a gelatin
mass, colored with Berlin blue or carmine, and Hoyer’s lead
chromate yellow gelatin mass; or, for tracing out fine vessels
and histological work, a saturated aqueous solution of Berlin
blue may be used.

Berlin blue can be purchased in the form of a dried precipi-
tate and this dissolved in water, but a more satisfactory solution
is obtained by following the directions of Mayer (54, p. 310).
A solution of 10 c.c. of tincture of perchloride of iron, or a
saturated solution of ferric trichloride, in 500 c.c. of water is
added to a solution of 20 grams of yellow prussiate of potash in
500 c.c. of water. This mixture is allowed to stand for 12
hours. ‘The yellow fluid at the surface is then poured off, the
remainder filtered and the filtrate washed with distilled water
until the washings come through dark blue. Enough water is
then added to completely dissolve the precipitate. This should
make about a liter of concentrated solution of Berlin blue.

If a gelatin solution is desired, use from 10 to 20 parts of the
Berlin blue solution to one of the gelatin. I usually take 25
grams of gelatin to 100 c.c. of water; heat in the same water
bath with 200 or 300 c.c. of the Berlin blue solution. When
the gelatin solution is melted, add to it, slowly, the Berlin blue
solution; the mixture is then heated until the precipitate, which
is usually formed, disappears. Then filter through a flannel.
If the mass is to be kept some time, add a little chloral hydrate.
For fish vessels it is best to inject the mass as cool as possible.

floyer’s Yellow Lead Chromate Gelatin Mass (see Lee’s
Vade-Mecum, p. 304) is a very simple mass to make. Prepare
2 bottles of stock solution; in one, make a saturated aqua
solution of potassium bichromate, and in the other a saturated
solution of lead acetate. Then soak up 25 grams of gelatin in
100 c.c. of water; heat to melting point in a water bath; add
100 c.c. of the potassium bichromate solution. Afterward heat
nearly to the boiling point; add 100 c.c. of the lead acetate
solution, and filter through a flannel. It is best to make this

BLOOD-VASCULAR SYSTEM OF THE LORICATI Bolt

mass shortly before using. This mass has a beautiful yellow
color, having a very fine precipitate, which easily passes
through the fine capillary net-works of the gills, pseudobranchie,
and retia mirabilia of the eye.

A carmine solution is prepared by mixing some carmine with
water; enough ammonia is added to dissolve the carmine, giv-
ing it a dark brown color. The mass is then neutralized with
acetic acid, and when neutral it will change to a bright red
color. If desired to keep for some time, add chloral hydrate.
Like the Berlin blue solution it can be injected as it is; or it
can be mixed with a gelatin mass in the same proportions.

2. Apparatus.

The apparatus consisted of a number of glass cannulas of
various sizes, fastened to short, but stout rubber tubes; a 4-oz.
rubber syringe, and a % oz. rubber syringe. The latter,
when connected with a rubber tube and a small glass cannula
makes the best kind of a hypodermic syringe.

3. Mode of Procedure.

When the arteries and veins are to be injected with different
colors, it is best to inject the venous system first. This can
generally be accomplished from the hepatic vezn (PI. I, fig. 1,
Hep.V.). <A ligature is placed under the vein and tied loosely ;
a slit is made in the anterior portion of the liver, and a large
cannula attached to a rubber tube is forced cephalad in the vein
into the szmus venosus. 'The blood was sucked into the tube,
and then blown out; this process was repeated, until the sinus
and other vessels were cleared of blood, and the cannula was
again inserted into the vein and ligatured. Then the syringe
was filled with the yellow injecting mass, but before connecting
with the rubber tube, all the air possible should be sucked out
of the tube, sinus, and other vessels. With a slow steady stroke
the mass is forced into the sinus venosus; from thence through
the heart to the gills; through the precava to the jugular and
cardinal veins, and usually it would pass through the other
hepatic vein and the venous capillaries of the liver, thus filling
the portal system. If this fails, the portals can easily be in-
jected from the posterior mesenteric vein (Pl. I, fig. 1; P.Mes.-

a2 ALLEN

V.); or, if this vessel is absent, from one of the intestinal veins.
If desirable to fill the caudal, neural, and hemal veins, a sepa-
rate injection of the caudal vein (fig. 1, Cau.V.) is usually re-
quired. The entire arterial system can be filled from one of
the gastric arteries (fig. 1, L.Gas.A.), but an easier and more
satisfactory way, especially if the fish has no air-bladder, is to
make 2 injections of the dorsal aorta at a point marked X (fig.
1), shortly before it penetrates the kidney and posterior to the
origin of the cceliaco-mesenteric and subclavian arteries. A
cannula the proper size, having a rubber tube attached, was
slipped cephalad into the vessel and ligatured. If the aorta is
small, the rubber tube and cannula can be used as a blow pipe
to help open itup. The syringe is then filled with the Berlin
blue injecting mass; as much air as possible is sucked out of
the tube and vessels before connecting the tube with the syringe ;
with a slow, steady movement, the mass is forced cephalad into
the aorta, from whence it passes into the carotids, efferent bran-
chial vessels, cceliaco-mesenteric and subclavian arteries, and
finally in like manner, from the same place, the aorta is in-
jected caudad, which fills the vessels of the kidney, reproduc-
tive organs, body wall, and tail.

In tracing out the small peripheral vessels of the head, fins,

and viscera, I have found it very satisfactory to inject alone
the head, fins and viscera of a 15 to a 40 pound fish. The
head is severed dorsally several inches behind the skull, includ-
ing the pectoral and ventral fins, being careful not to cut or
injure any of the visceral organs. A ventral slit is then made
through the entire ventral wall to the vent; the intestine is cut
at the rectum, and the entire viscera pulled out with the head.
In this manner the fish is cleaned, spoiling very little if any of
the flesh, after which the 2 cut ends of the cardznails (Pl. I, fig.
1, L. & R.Car.V.), and the posterior end of the ventral artery
(Pl. Il, fig. 12, Ven.A.), if cut, were ligatured. Two injec-
tions, as described in the previous paragraph, were made; one
from the hepatic vern, and the other cephalad from the cut end
of the dorsal aorta.

In most cases it is best to make the dissections while the
material is fresh. Asa preserving fluid I find nothing better
than formalin; it does not extract colors as does alcohol, and

BLOOD-VASCULAR SYSTEM OF THE LORICATI 33

its action toward gelatin is favorable, hardening it considerably.
The coats of the eye are fixed in perfect shape, and such deli-
cate organs as the kidneys are quickly hardened, so that one
can cut cross-sections with a knife, which is a great help in
tracing out the renal-portal system.

If a histological injection is required, slit the s7us venosus
and wash out the blood vessels, cephalad, from the dorsal aorta;
then inject with an aqua or thin gelatin Berlin blue mass, or
with Hoyer’s yellow chromate mass, freshly prepared. The
mass is allowed to set and the injected organs are thrown in
toto into Miiller’s fluid, or better still, cut up into small pieces
and thrown into any well known fixing fluid that will not extract
the colors. Injected material thus fixed can be kept some
months in alcohol, but it is best to imbed as soon as possible.

If the bile vessels are to be injected, it can be accomplished
by slitting the ductus choledochus, near its exit into the intestine
or pyloric ceca. A hypodermic syringe filled with the Berlin
blue mass is inserted into the duct, toward the gall-bladder, fill-
ing first the bladder, then the hepatic ducts, and finally, if suc-
cessful, the gall-capillaries.

III. HISTORICAL REVIEW.

To Duverney (13),* in 1699, 62 years after the discovery of
the blood-vascular system by Harvey, and 38 years after the
discovery of the capillaries by Malpighi, belongs the honor of
first explaining the structure of the fish heart; and 2 years later
(14) he described and figured the circulation in and about the
gills of the carp; he erred, however, in finding but one branchial
vessel in a branchial arch. Monroe (48) in 1787, was the first
to describe correctly the circulation in the gills. He injected
the ventral aorta and examined the gill-filaments under a micro-
scope; he also noticed the efferent branchial vessels, uniting to
form the carotids, cceliaco-mesenteric, dorsal aorta, and the sub-
clavians, and observed the coronary and other vessels coming
from the ventral ends of the efferent branchial vessels; as well
as the jugular, portal, and renal-portal systems. According to
Miiller (50), Albers (1) in 1806, was the first to notice the cho-
roid gland of the eye, and observed that the vessels in the cho-

* All figures in brackets refer to bibliography at the end of the paper.

34 ALLEN

roid coat arose from this plexus. The first volume of Cuvier
and Valenciennes’ great work on fishes (11) issued in 1828, con-
tains a short general description of the circulation of Perca, with
2 excellent plates, which show practically all the vessels, in-
cluding the afferent and efferent pseudobranchial arteries, and
10 years later, Jones (41) carefully described and figured the
retia mirabilia of the eye.

About this time marked the beginning of the classical writings
of Hyrtl, Miller, Vogt, and Stannius. Between the years 1838
and 1872, Hyrtl published at least 7 different papers on the cir-
culation of fishes, but unfortunately I have had access to only a
few of them. Miller (50) tells us that in the first one (30) the
author made a microscopical examination of the gill-filaments,
and showed that they contained no lymphatic vessels, as had
been claimed by some previous investigators. He also explained
correctly the course of the blood from the hyoidean artery to the
pseudobranchiz, and from thence to the eye. With Hecht, he
noticed the pseudobranchial artery coming from the circulus
cephalicus. In 1852, Hyrtl (32) described with considerable
detail the arterial system of Lefzsosteus, and 6 years later the
arterial system of the roaches (34). One of the best general
works on the circulation of fishes is to be found in part IV of
Miiller’s famous work on Myxinoiden (50), consisting of 130
pages and 5 plates. He takes up almost the entire circulatory
system of cyclostomes, selachians, and several teleosts in a com-
parative way, going into great detail over the blood supply of
the pseudobranchiz, choroid gland, and air-bladder. Vogt’s
splendid monograph on the Anatomy and Embryology of the
Salmon was published in 1845, but unfortunately I could get
access only to the plates, of which several were devoted to the
adult, and many others to the development of the circulatory
system in the embryo. In Stannius’ Handbuch der Anatomie
der Wirbelthiere (74), there is a brief, but perhaps the best, gen-
eral description of the circulation in the several groups of fishes ;
there are, however, no plates. The author does not go into
quite as much detail regarding the blood supply of the pseudo-
branchia, eye, and air-bladder as Miiller, but goes into more
detail concerning the larger trunks and the vascular supply for
the visceral organs.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 35

During the last half century quite a number of important
papers have appeared on the circulation of different species of
fishes, or confined to the circulation of various organs, and a
few are devoted to the embryology and physiology of the blood
vessels. First under this head might be mentioned the first vol-
ume of Owen (58), which was issued in 1866. The author
gives a very good comparative description of the circulation in
several groups of fishes. Ten years later Stohr (75), described
the number and arrangement of valves in the conus arteriosus
of selachians and ganoids. In 1880, Emery (24) put out his
monograph on the genus Fverasfer. This volume contains a
short, but accurate account of the circulatory system and 2
most excellent colored plates; the first one consists of a figure
of the entire arterial system, a similar figure of the venous sys-
tem, and several figures showing the blood supply in the kid-
neys; while the other plate is devoted to the blood vessels in
the organs. The same year T. J. Parker published a paper, to
which I have not had access, on the venous system of the skate,
fraja nasuta (59). In 1884, McKenzie published a most excel-
lent paper on the catfish, Amezurus catus (52). He gives one
figure showing the union of the efferent branchial arteries to
form the carotids, dorsal aorta, etc., and finds the pseudo-
branchiz, though only rudimentary, located on the main inter-
nal carotid artery, and not on a branch of the external carotid
or hyoidean artery as is the case with bony fishes in general. In
Marshall and Hurst’s Zodlogy (53), there is one figure and a
very good description of the circulation of the dogfish, Scy/-
fium canicula. By far the best account that we have of the cir-
culation of selachians is found in T. J. Parker’s memoir on
Mustelus (60), which was published in 1886. It contains 47
pages and 4 most excellent colored plates. The author gives a
brief synonymy of the blood vessels, and his methods of inves-
tigation. Unfortunately I did not gain access to this valuable
paper, until my own work was nearly completed. Mayer (55),
in 1888, gives a detailed account of the circulation in the fins
of selachians, with 2 colored plates. The author gives the
technique employed and favors an aqua solution of Berlin blue
for an injection mass. The so-called peripheral lymphatic ves-
sels described by Hyrtl, Miiller, and Stannius, he considers as

36 ALLEN

veins. An excellent account of the embryology of the heart
and blood vessels was given by Hoffman (39) in 1893. In
Vogt and Yung’s Anatomie, vol. 2, there is found a brief, but
excellent account of the circulatory system of the perch, with 2
colored plates. T.J. Parker (61) in his Zodtomy, 1895, gives
the general outline of the circulation in the skate, raza nasuta,
with 2 figures, and also a similar description and one figure on
the circulation of the cod, Gadus morrhua. Inthe first few
pages of Allis’ paper on Amza (3), there is a detailed account
of the circulation in the head region, illustrated by several
beautiful colored plates. To Jordan and Evermann (45) in
1898, we are indebted for a systematic arrangement of the fishes
and fish-like vertebrates of North America. In 1g00, Allis (4)
published a complete account of the development of the pseudo-
branchial circulation in Aza, and lastly, Briinning (10) in the
same year was the first to work out in any detail the physiology
of the blood vascular system of fishes. To this list might be
added the general comparative anatomies of Gegenbour (26 and
27) and Wiedersheim (86 and 87).

SECTION II. TEXT.
IV. GENERAL SURVEY OF THE BLOOD VESSELS IN OPHIODON.

Since the blood of a fish passes around in a circle, it matters
but little where we begin. A simple glance at Pl. I, fig. 1, will
give an idea of the general course of the blood. The entire
venous blood is poured into the szzus venosus (Pls. I and II,
figs. 1 and 12; Sin.Ven.), through 6 large sinus-like vessels.
From the rear come the hepatic veins (Pls. I and II, figs. 1 and
12; Hep.V.), which through the capillaries of the liver receive
the Jorial wes (P1. 1, figs. 1, 6, andia1; I. and R-Por.V*);
bringing the venous blood from the viscera; and the ventral
vers (Pl. I, fig. 12; L. and R.Ven.V.) conveying the blood
from the ventral or pelvic fins and the body walls. From either
side, the sinus venosus receives 2 large lateral trunks. The
posterior ones or subclavian sinuses (Pl. II, fig. 12; Sub.S.)
are the smaller, containing venous blood from the outer or
abductor muscles of the pectoral fins; and the anterior or larger
ones are the precaval veins or ductus cuvteri (Pl. Il, fig. 12;
Prec.V.), which receive the venous blood from the rest of the

BLOOD-VASCULAR SYSTEM OF THE LORICATI 37

body. Close to the sinus venosus the right precava receives
the znferzor jugular vern (Pls. I and II, figs. 1 and 12; I.J.V.),
returning the venous blood from the branchial muscles and
the pharynx. Passing dorsad around the cesophagus, each
precava arises at the ventral surface of the head kidney from 2
large trunks; the cephalic vessels or jugular veins (Pls. I and
II, figs. 1, 5, and 12; R. and L.J.V.) convey the venous
blood from the face, nose, eyes, brain, and dorsal branchial
muscles and their arches; and the caudal vessels or cardinal
veins (Pl. I, figs. 1 and 5; R. and L.Car.V.) vary greatly in
length and in size. The short left cardinal returns blood only
from the left head kidney; while the large right cardinal arises
in the posterior end of the kidney and through the renal vezns
(Pl. I, figs. 1 and 10; A. and E.Ren.V.) receives blood from
the caudal vein (Pl. I, figs. 1 and 10; Cau.V.) coming from
the tail in addition to collecting blood from the thoracic walls,
reproductive organs, and viscera.

From the sinus venosus, the blood passes into the aurzcle or
atrium (Pls. I and II, figs. 1 and 12; Aur.), through the ven-
tricle (Pls. I and Il, figs. 1 and 12; Ven.) into the dalbus
artertosus (Pls. I and II, figs. 1 and 12; B.Art.), from whence
it is forced through the ventral aorta or branchial artery (Pls.
I and It, figs: /1-and 12:'V.Ao-) into 4 pairs of afferent
branchial arterzes (Pls. I and II, figs. 1 and 12; A.Br.A.),
(the third and fourth pairs, however, arise as one trunk, but
soon divide), which run in the posterior grooves of their corre-
sponding arches. These vessels exhaust themselves in numer-
ous afferent filament arteries (Pl. I, fig. 2; A.Fil.A.), which
pass along the inner edge of each branchial filament and which
are collected on the opposite or outer side by the eferent filament
arterzes (Pl. I, fig. 2; E.Fil.A.), after having passed through
a fine capillary network, where the blood is purified by the
oxygen held, physically, in the water. These efferent filament
arteries, containing pure arterial blood reunite, forming the
efferent branchial arteries (Pls. I and II, figs. 1, 5, and 12;
E.Br.A.), which run parallel, but cephalad to the afferent
branchial arteries. From the ventral ends of these efferent
vessels are given off the hyordean artery (Pls. I and II, figs. 1
and 12; Hyo.A.) for the hyoid arch and tongue, and which

38 ALLEN

anastomoses with the facialis-mandibularis branch of the exter-
nal carotid forming the mandibular artery; the pharynx artery
(Pl. II, fig. 12; Phar.A.) for the ventral branchial muscles,
from which the coronary artery (Pls. I and II, figs. 1 and 12;
Cor.A.) arises; the ventral artery (Pls. I and II, figs. 1 and 12;
Ven.A.) for the ventral or pelvic fins and the ventral body
walls; and several smaller arteries, which will be described in
detail further on. Dorsally the efferent vessels send off anteri-
orly the common carotid arteries (fig. 1; C.Car.A.), which
supply the face, orbit, nose, and brain; and posteriorly the
efferent branchial vessels unite in forming the c@/zaco-mesen-
teric artery (Pl. I, figs. 1 and 5; Coe.Mes.A.) for the viscera ;
the subclavian arteries (figs. I and 5; Sub.A.) for the pectoral
fins; and the dorsal aorta (figs. 1 and 5, D.Ao.) for the body
walls, tail, kidney, and reproductive organs. The union of
these efferent branchial vessels to form the internal carotids
anteriorly and the dorsal aorta posteriorly, forms what is known
as the czrculus cephalicus.

V. Hears.

This organ, which is inclosed in the triangular cardiac space,
lies in the ventro-median line directly cephalad of the pectoral
arch. The pharnyx forms the roof of this cavity, the thick sterno-
hyoideus muscle the floor, and together with the pharyngo-clav-
icularis internus muscles it makes up the lateral walls; while
the aponeurotic membrane forms the posterior wall that sep-
aratés the cardiac cavity from the visceral cavity. This cham-
ber is lined with the pericardium, which, like the peritoneum,
consists of a parietal and visceral layer; the former lines the
cavity and the latter loosely envelops the heart, being attached
anteriorly to the ventral aorta in the region of the first afferent
branchial vessels and posteriorly to the dorsal and ventral wall
of the precava. The space between the parietal and visceral
layers is known as the outer pericardial cavity or pericardial
lymphatic sinus, for it is in direct communication with the lym-
phatics ; while the space between the heart and the visceral layer
is known as the inner pericardial or pericardial cavity proper.
No connections were noticed between these 2 cavities.

As in the other vertebrates the heart is the center of activity ,

BLOOD-VASCULAR SYSTEM OF THE LORICATI 39

however, it contains only venous blood. The heart proper con-
sists of 2 chambers: a dorsal one, the auricle, and a smaller
ventral one, the ventricle. The entering blood comes into the
auricle posteriorly, from the thin-walled sinus venosus, from
whence it is forced ventrad into the ventricle and then out an-
teriorly into the elastic bulbus arteriosus.

Stnus Venosus (Pls. 1, II, and VI, figs. 1, 12 and 39; S. Ven.
and Sin. Ven.).—When inflated the dimensions of this thin-
walled sinus are about equal. In a 4o lb. Ophiodon this cham-
ber measured 38 mm.'in length from the entrance of one
precaval vein to the other, 32 mm in breadth from the sinu-
auricular valves to the entrance of the hepatic veins, and 28
mm. in height at the center. The large sinus-like vessels
emptying into this sinus have their inner edges reflected inward
in the form of flaps, which tend partly to close the openings in
case of a reverse current. In a like manner the walls of a sinus
venosus, after having united with the outer connective tissue
layer of the auricle, are reflected inward to form the s¢mz-auric-
ular valves (Pl. VI, fig. 39; S.A.V.). Some fishes are said to
have a dorsal and a ventral flap, but in Ophzodon they have
become fused, forming a continuous circular flap, which de-
creases the size of the sinu-auricular opening by at least one-
half.

Auricle (Text-figs. 1 ead; Pls. I, Il, and VI, figs. 1, 12, 39
and 40; Aur.).—This triangular, saddle-shaped reservoir, con-
vex above and concave below, is much larger than the ventricle,
when inflated. It extends over three-fourths of the ventricle ; its
anterior apex extends cephalad over the bulbus arteriosus some
little distance, and posteriorly the auricle ends in 2 lateral horns.
In this specimen the auricle measured 34 mm. in length, from
its apex to the sinu-auricular valves, and if the posterior horns
were included, the length would have been increased by at
least 10 mm. The greatest width is in the neighborhood of the
- posterior horns, where it is 40 mm., and the greatest height
amounted to something like 22 mm. The walls of this cham-
ber consist of 2 layers, an outer coat of connective tissue

1 All measurements pertaining to the heart were taken from a 4o lb. Ophi-

odon’s heart, which had previously been injected with a gelatin mass and hard-
ened in formalin. ‘

40 ALLEN

(Text-figs. 1 and 2, and Pl. VI, fig. 39; C.T.) and an inner coat
composed of muscle bands, the ¢radbecule carne (Pl. V1, fig.
39; T.C.A.). These muscle bands run in every direction, but
mostly dorso-ventrad, and between these bands there are large
blood cavities, which increase in size toward the central cavity,

FIG. 1.

the muscular layer becoming more and more compact toward
the surface. The central cavity occupies a large portion of the
auricle and is continued into the posterior lobes. Penetrating
the floor of the auricle, a little caudad of the center, is the aurz-
culo-ventricular opening (Pl. VI, fig. 39; A.V.O.), through

BLOOD-VASCULAR SYSTEM OF THE LORICATI 41

which, by the contraction of the trabecule of the auricle, the
blood from the auricle is forced into the ventricle. In order to
prevent a back-flow of blood, this passage ¢an be entirely closed
by 2 auriculo-ventricular valves (Pl. VI, figs. 39 and 4o; and
Text-fig. 1; A.V.V.), respectively anterior and posterior in
position and which when closed appear like 2 inverted cups from
the auricle side, having their inner edges free. These valves
are formed by the union and a thickening of the outer layer of
connective tissue from the auricle and the ventricle.

Venice (Next-nos. pratid 2; Pls.'1, Wand: VI, '‘fias..7, 12,
39 and 40; Ven.).— The ventricle, which is 42 mm. long by

Sod
SS

Seeder ee Seeeees

27 mm. wide in this specimen, is shaped something like a 4-
sided pyramid. Beginning bluntly, it gradually increases in
width and then rapidly tapers down into a posterior apex. The
ventricle has one more layer than the auricle. Outside is the

‘

42 ALLEN

connective tissue layer (Text-figs. 1 and 2, and Pl. VI, EOE}
C.T.), which is continuous with the corresponding layer of the
auricle and where such union takes place, the layer becomes
much thicker (see Text-fig. 1). The trabecule carne of the
ventricle (Pl. VI, fig. 40; T.C.V.) resemble the trabecule of
the auricle close to the outer connective tissue layer, the blood
cavities being very small. In addition to the 2 layers of the
auricle, the ventricle has a thick mascular layer (Pl. VI, fig.
40; M.L.) between the trabeculae carne and the outer connec-
tive tissue layer, containing no blood spaces. The central cav-
ity of the ventricle (Pl. VI, figs. 39 and 40; C.C.V.), which
runs close to dorsal wall, is much smaller than the central cav-
ity of the auricle. The anterior end of this cavity is continuous
with the posterior end of the bulbus arteriosus, which represents
the well developed conus arteriosus (Pl. VI, fig. 40; C. Art.) of
the Elasmobranchs and Ganoids. ‘The entrance into the conus
arteriosus is guarded by 2 semz-lunar valves (Text-fig. 2 and
Pl. VI, fig. 40; S.V.), dextrad and sinistrad in position and
having their inner margins free. These valves are similar to
the auriculo-ventricular valves, except that each valve has 2
cephalic processes, which continue along the dorsal and ventral
walls of the bulbus arteriosus. A reverse current, caused by a
retraction of the elastic walls of the bulbus, would entirely close
these valves, allowing no blood to return to the ventricle.
Bulbus Arteriosus (Pls. 1, Il and VI, figs. 1, 12 and 4o, and
Text-fig. 2; B. Art.).— After leaving the ventricle the bulbus
rapidly increases in diameter and then gradually tapers down
into the ventral aorta or branchial artery (Pls. I. and II, figs.
1 and 12; V.Ao.), which gives off the paired afferent branch-
ial vessels to the gills. The walls of the bulbus are quite thick
and the internal layers are thrown into longztudinal ridges or
folds (Pl. VI, fig. 40; L.F.). The bulbus is richly supplied
with blood vessels, which will be described later on.
Microscopical Structure of the Heart (Text-figs. 1 and 2).—
A transverse section through one of the auriculo-ventricular
valves (Text-fig. 1) shows us that the outer connective tissue
layer is greatly thickened in the dorsal portion of the auricle and
at the union with the same layer of the ventricle. As in other
vertebrates the muscle fibers are striated and run in all direc-

BLOOD-VASCULAR SYSTEM OF THE LORICATI 43

tions, but for the most part they can be grouped under the head
of Jongitudinal muscle fibers (Text-fig. 1, L.M.) and ¢ransverse
muscle fibers (Text-fig. 2, T.M.). At various places the muscle
fibers penetrate the connective tissue layer and very often fibers
from the auricle would pass entirely through this layer into the
ventricle. The auriculo-ventricular valves are merely a por-
tion of the combined outer connective tissue layer, having their
inner margins free, but having their outer edges securely bound
down by muscle fibers. About the only difference in structure
between the auricle and the ventricle, aside from the relative
sizes of their central cavities, is the difference in the density of
their muscle fibers. In the ventricle the blood cavities are very
small, while in the auricle they are of considerable size, but
growing smaller peripherally, and in the ventricle these cavities
give place entirely to muscle fibers, peripherally. Cephalad in
the ventricle the connective tissue gradually increases about
the central cavity, marking the beginning of the conus arterio-
sus. In 2 places folds of connective tissue pass entirely through
the central cavity or conus as it is at this place. They are the
semi-lunar valves (Text-fig. 2, S.V.). In places can be seen
traces of elastzc muscle fibers (Text-fig. 2, E.M.F.) and round
endothelium cells (Text-fig. 2, End.). While it is not the pur-
pose of this paper to demonstrate the presence or absence of a
layer of endothelium lining the central cavity of the heart, it
may be said, however, that my sections did not show anything
that I could positively identify as endothelium, until the origin
of the conus was reached; nevertheless a silver impregnation
would have doubtless revealed its presence. The walls of the
bulbus are formed from 3 coats. ‘The external coat, tunica ex-
terna or adventitza presents no peculiarities ; it is composed of
longitudinal bundles of connective tissue, in which run the main
nutrient vessels. Next comes the ¢uzz¢ca medza or middle coat,
which is very thick and forms the longitudinal folds shown in
fig. 40, which decrease in height as you go toward the ventral
aorta. This tunic is constructed out of circular muscle fibers,
in which run many white elastic fibers. The internal coat or
tunica interna, which is made up of a longitudinal network, is
bounded internally by a layer of large round endothelial cells.

44 ALLEN

VI. PERIPHERAL DISTRIBUTION OF THE ARTERIES.

1. Branchial Arteries.

As has already been stated in the paragraph on the general
survey of the blood vessels, the aferent branchial arteries (Pls.
I and II, figs. 1 and 12; A.Br.A.) are paired vessels, which
convey the venous blood from the ventral aorta or branchial
artery (Pls. I and II, figs. 1 and 12; V.Ao.) to the branchial
filaments.. They arise as 3 paired trunks from the ventral
aorta. The most cephalic pair supply the filaments of the first
branchial arches; the second pair the filaments of the second
branchial arches; and the third pair soon divide, the anterior
forks supplying the third pair of branchial arches and the pos-
terior forks, the last or fourth pair of branchial arches.” All of
these vessels, which very closely resemble one another, run in
the grooves of their respective arches and gradually exhaust
themselves by giving off numerous afferent filament arteries
throughout their entire dorsal course.

The (Averent Brauthial Telament’ Vessels (Pl. 1, tig. 25
A.Fil.A.) of 2 adjacent filaments arise as paired vessels, and
running in a caudal direction along the inner or hypothenuse
margins of their respective filaments, gradually exhaust them-
selves in numerous afferent filament cross-vessels, which are
only about 60 # apart. Proximally these vessels attain a con-
siderable length, but gradually decrease in length distally.
Each cross-vessel terminates in a dorsal and a ventral vessel,
from which the filament capillary network (P\. I, fig. 2; Fil.
Net.) arises. This network lies in a dorso-ventral plane in-

1A gill or holobranch is composed of a double row of filaments or 2 hem?-
branchs attached to the concave or posterior side of each branchial arch. These
filaments have the form of right-angled triangles, attached by their short sides
to the arches and the hypothenuse sides of each pair face one another. Each
pair of filaments is not separated by a cartilaginous rod as is the case with the

Elasmobranchs, but they usually overlap one another to some extent at their
bases.

? This appears to be the normal arrangement among the Teleosts; while in
the skate one trunk may supply several branchial arches, and in the ratfish
(Hydrolagus), I have observed that the ventral aorta gives off a pair of vessels
for each pair of branchial arches.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 45

closed in a vascular plate’ and is separated from the current of
water passing between the gills by a thin membrane. By
osmosis the carbon dioxide from the blood is exchanged for the
oxygen held in the pores of the water. Ina like manner the
pure blood is collected into a pair of dorso-ventral vessels,
which unite, forming a short efferent filament cross-vessel.
These vessels in turn form the efferent branchial filament arter-
zes (Pl. I, fig. 2; E.Fil.A.), which run cephalad along the
outer margins of the filaments and which in turn empty into
and form a common trunk, running in the posterior groove of
each branchial arch, namely, the efferent branchial artery.
These efferent branchial arterzes (Pls. I and II, figs. 1, 2,
5, and 12; E.Br.A.) very closely resemble one another. They
run parallel, but cephalad to the afferent branchial vessels; be-
ginning ventrally they increase in size dorsally. For the most
part the efferent filament arteries are poured directly into the
main efferent branchial trunks, but dorsad and ventrad they
empty into a branch of that vessel. The ventral branch takes
its origin from paired vessels, which lie immediately caudad and
to either side of the large efferent branchial trunk. They re-
ceive first the most ventral pair of efferent filament arteries ;
then in their dorsal course take up in succession from either
side the several following efferent filament arteries, and after
having received 20 or 30 such vessels, unite, forming a short
trunk, which empties into the main efferent branchial trunk
from the rear. In like manner the dorsal branch arises as a
paired vessel and returns the blood from seveyal of the most
dorsal fiaments. There is also a gradual variation in the point
where the various efferent branchial arteries leave their respec-
tive branchial arches. The first or most anterior efferent
vessel follows along the posterior edge of the cerato- and epi-
branchials some little distance beyond the dorsal-cephalic bend ;
while the fourth or posterior efferent branchial vessel leaves
the cerato-branchial a little below the dorsal-cephalic bend ; and
the efferent branchial vessels of the second and third branchial
arches come in midway between these extremes, forming a
regular series of intergradations. Ventrally the first, second

1 Each branchial filament is divided up into numerous parallel vascular
plates or lamelle, which lie in dorso-ventral planes.

¢

46 ALLEN

and third efferent branchial arteries on one side anastomose
with the corresponding trunks of the opposite side. From
either side of the ventral point of union of the first pair of effer-
ent vessels, a large hyordean artery (figs. 1 and 12, Hyo.A.) is
given off to the hyoid arch and mandibular region. The ven-
tral points of union of the second and third pairs of efferent
branchial arteries mark the source of the ventral artery (Pls.
I and II, figs. 1 and 12; Ven.A.); and the pharynx artery (Pl.
II, fig. 12; Phar.A.) may arise form either of the third efferent
branchial arteries. From the dorso-cephalic surface of the first
pair of efferent branchial vessels, the 2 common carotid arter-
tes (Pl. I, figs. 1 and 5; C.Car.A.) are given off cephalad; con-
tinuing dorso-caudad, the first efferent trunk unites with the
second to form the frst or antertor epibranchial artery (Pl. I,
fig. 5; Epbr.A.(,)), and in like manner the third and fourth
efferent branchial vessels unite to form the second or posterior
epibranchial artery (Pl. I, fig. 5; Epbr.A..). The epibranch-
ial vessels on one side unite with the corresponding trunks on
the opposite side, forming a common chamber (Pl. I, fig. 5;
C.C.), which lies in a median line ventrad of the basi-occipital.
This chamber is the source of several large trunks; the dorsal
aorta (Pl. I, figs. 1 and 5; D.Ao.) arising from the left posterior
dorsal corner; the ca@léaco-mesenteric (Pl. I, figs. 1 and 5; Cee.
Mes.A.) below and to the right; and the common subclavian
trunk (Pl. I, fig 5) lies above the aorta and the cceliaco-mesen-
teric artery. In one case the subclavians were seen to arise
separately. The left one had its origin in the same place as
the common subclavian trunk, and the right one came from the
cceliaco-mesenteric artery.

2. Arteries Arising From the Ventral Ends of the Efferent
Branchial Arteries.

First under this head might be mentioned the 2 little Ayo hyozd-
eus tnfertor arteries (Pl. II, fig. 12; Hys.A.), which arise from
the cephalic surface of the first efferent branchial arteries just
before they unite ventrally. These vessels run cephalad a short
distance and then spread out laterad over the dorsal surface of
their respective muscles.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 47

Hyoidean Arteries (Pls. I and II, figs. 1 and 12; Hyo.A.).
— A short distance above the source of the inferior hyo hyoideus
arteries, 2 large hyoidean arteries are given off to the hyoid
arch and the adjacent region. After reaching the hyoid arch
from the inside, a little behind the hypohyals, the main trunk
runs along the dorsal surface of the cerato- and epi-hyals;
making a dorsal bend in front of the interhyal it crosses under
the preopercular, and after passing through a foramen, which
is formed by the symplectic, hyomandibular, preopercle, and
quadrate, anastomoses with the /aczalis-mandibularis artery
(Pl. I, fig. 1; F.Man.A.). In the embryo the hyoidean artery
probably furnished the entire blood for the pseudobranchia; the
current of blood in the facial-mandibular artery was dorsad
toward the carotids. Also in the adult it would be possible for
the blood from the hyoidean artery to flow dorsad in the facial-
mandibular artery as well as ventrad, however, since the facial-
mandibular is a much larger artery than the hyoidean, it is not
probable that much of the blood from the hyoidean artery runs
counter to the current of the facial-mandibular artery. It also
might be possible at times for the blood in the hyoidean artery
to flow ventrad, that is toward the efferent branchial artery.
From Miiller’s (50), Stannius’ (74), and Emery’s (24) descrip-
tions, one would infer that the hyoidean artery in most bony
fishes supplied the pseudobranchia, but in Ophzodon the blood
supply for the pseudobranchia, which will be considered later,
comes from a branch of the external carotid artery.

The first branch to be given off from the hyoidean artery is the
lingual artery (P\. Il, fig. 12; Lin.A.). This vessel leaves the
hyoidean artery close to the efferent branchial artery, shortly be-
fore the hyoidean artery reaches the hyoid arch, and each lingual
artery runs cephalad along the ventral surface of the glossohyal.
Immediately after the hyoidean artery reaches the hyoid arch it
gives off the genzohyoideus artery (Pls. I and II, figs. 1 and 12;
Ghs.A.) to the geniohyoideus muscle. One of these arteries is
much longer than the other ; sometimes it is the right and again it
is the left. Inthe specimen from which fig. 12 was drawn, the
right artery was the longer ; it passed entirely around to the outer
ventral surface of the ceratohyal and then curved cephalad, pass-

48 ALLEN

ing obliquely along the ventral surface of the right geniohyoideus
muscle and above the right hyohyoideus inferior muscle. When
the median line between the 2 geniohyoideus muscles is reached
this vessel bifurcates, one branch running along the ventral sur-
face of each geniohyoideus muscle. Both of these forks supply
also the intermandibularis muscle. The short geniohyoideus
artery, which is the left one in this specimen, supplies only the
posterior part of the left geniohyoideus muscle. The largest of
the branches of the hyoidean artery is the hyoid arch artery
proper, which has been designated as the dranchiostegal artery
(Pls. I and II, figs. 1 and 12; Br.O.A.). This vessel is given
off a little cephalad of the interhyal and runs along the outer
ventral edge of the epi- and cerato-hyals. In the region of
each branchiostegal ray an artery is given off ventrad to supply
the hyohyoideus superior muscles. In Scorpenichthys one
branchiostegal artery does not supply all of the superior hyoi-
deus muscles. Three or 4 such vessels pass over the outer
surface of the epi- and cerato-hyals and supply from 1 to 3
hyohyoideus superior muscles; the last one evidently corre-
sponds to the single branchiostegal artery of Ophiodon.

What might be called the ¢hyrozd artery (Pl. II, fig. 12;
Thyr.A.) arises either from the second right or the second left
efferent branchial artery. In Fig. 12 it arises from the second
right efferent artery, flows cephalad under the ventral aorta
and anastomoses with the first efferent branchial artery. Along
its short course 2 or 3 small branches could be traced to the
thyroid gland, one of them supplying also the second left
obliquus ventralis muscle.

Pharynx Artery (Pl. Il, fig. 12; Phar.A.).— This vessel
may have its source from the third left or the third right efferent
branchial artery. In the specimen from which fig. 12 was
drawn it arose, caudad, from the third right efferent branchial
vessel and, passing obliquely over the ventral aorta it bifurcates
in the region of the combined afferent trunk of the third and
fourth branchial arches. The smaller right pharynx artery
(Pl. I, fig. 12; R.Phar.A.) supplies the right side of the
pharynx, the transversus ventralis muscle, and the right phar-
yngo-clavicularis externus and internus muscles; while the

BLOOD-VASCULAR SYSTEM OF THE LORICATI 49

larger left pharynx artery (Pl. II, fig. 12; L.Phar.A.) sup-
plies the pharynx and similar muscles on the left side. Soon
after the left pharynx artery leaves the main stem it gives
off the large coronary artery (Pls. I and II, figs 1 and 12; Cor.-
A.) for the heart. For some little distance this vessel runs
along the dorsal surface of the ventral aorta and then divides
into a dorsal and a ventral trunk. The dorsal coronary artery
(Pl. II, fig. 12; D.Cor.A.) continues along the dorsal surface of
the ventral aorta and bulbus arteriosus to the heart as the prin-
cipal vessel. Usually this vessel bifurcates in the region of the
conus arteriosus, one branch penetrating directly into the mus-
cular layer of the ventricle, while the other is a superficial vessel,
distributing itself over the dorsal surface of the ventricle; or
sometimes both may be superficial vessels. It is probable that
these vessels also supply the auricle, although I have never
been able to trace them further than the ventricle. Each of
these vessels gives off a small artery, which encircles the bul-
bus and anastomoses on the ventral side with the ventral coro-
nary artery, and from this circular artery several small vessels
are given off to the bulbus and the ventricle. The ventral
coronary artery (Pl. Il, fig. 12; V.Cor.A.), which is much
smaller than the dorsal vessel, also runs caudad in the outer
coat of the ventral aorta, but it supplies only the ventral walls
of the ventral aorta and the bulbus. None of its branches
reaches the ventricle. In Scorpenichthys the pharynx arteries
arise as separate arteries from the second pair of efferent
branchial arteries, and the coronary artery comes from the left
pharynx artery, close to its point of origin from the efferent
branchial vessel.

The Ventral Artery (Pls. I and Il, figs. 1 and 12; Ven.A.)
is the largest of any of the vessels arising from the ventral
ends of the efferent branchial arteries. In Ophzodon this ves-
sel has its origin from the ventral union of the second and third
pairs of efferent branchial arteries. This does not appear to
be the common arrangement among other bony fishes; in Hex-
agrammos, Scorpenichthys, and Sebastodes the ventral artery
has its source from the second pair of efferent branchial vessels.
Continuing caudad along the ventral surface of the pericardial

Proc. Wash. Acad. Sci., June, 1905.

50 ALLEN

cavity a little to the right of the median line, the ventral artery
gives off numerous branches to the sternohyoideus muscle. In
the specimen from which fig. 12 was drawn, a vessel was
noticed branching off to the left, passing horizontally under
the ventricle, and terminating on the left precaval vein in the
neighborhood of the left subclavian sinus. Directly caudad of
this vessel and a little cephalad to the crossing of the sinus
venosus, the ventral artery sends off a pair of vessels to the
ventral muscles of the pectoral fin. Each of these hypobranch-
tal arterzes (Pl. Il, figs. 12 and 14; Hypobr.A.) runs a short
distance caudad between the sternohyoideus and the pectoral
profundus adductor muscle, and then curves slightly dorsad,
passing between the inner surface of the coracoid and the pec-
toral profundus adductor muscle, giving off at least two branches
to the inner surface of the muscle; then curving slightly ven-
trad, penetrates the basal canal of the pectoral rays,’ and
anastomoses in this canal with the zzternal subclavian artery
(2) (Pl. Il, fig. 14; I. Sub.A..,,), but before entering this canal
the hypobranchial gives off a dorsal branch which passes be-
tween the pectoral profundus muscle and the brachial ossicles,
supplying the inner surface of the muscle. Continuing caudad,
the ventral artery passes under the sinus venosus between the
pelvic bones, giving off arteries to the body wall, the ventral
or pelvic fin muscles, and the ventral rays. The first con-
stant artery of any size to be given off from the ventral artery
after it reaches the ventral fin musculature is one which comes
out ventrad in a median line to the outer surface of the pro-
tractor muscle of the pelvic arch, where it divides at nearly
right angles, one branch supplying the left, the other the right
protractor muscle of the pelvic fins and the very large abductor
muscle of the ventral spine (fig. 12; Ab.V.S.). At various
intervals, usually alternating with the veins, the ventral cnter-
costal arterves (Pl. Il, fig. 12; V.Intc.A.) are given off between
every alternate pair of myotomes, and they anastomose with the
corresponding dorsal intercostal arteries. The ventral artery

‘Each pectoral fin ray consists of 2 separate halves, which are concave inside
and convex outside, and where their bases overlap the brachial ossicles in their
attachment to the shoulder-girdle, there is formed a rather large canal at the
base of the pectoral fin.

BLOOD-VASCULAR SYSTEM OF THE LORICATI Sil

also sends off several branches to the other abductor and ad-
ductor muscles, and shortly before the pelvic bones become
united posteriorly, the ventral artery makes a short dorsal bend
and bifurcates at right angles, one branch going to the basal
canal of the right ventral fin rays and the other to the left.
Each terminal branch of the ventral artery exhausts itself by
giving off a branch to the core of each ray; proximally this
vessel runs in the center of the cavity, but soon divides, one
branch continuing caudad along the right side of the cavity,
the other the left. Usually from the left branch of the ventral
artery, but often from the right, a median vessel is given off
caudad, which passes along the ventro-median line between the
2 great lateral muscles and exhausts itself in numerous inter-
costal arteries.

This series of complicated vessels arising from the ventral
ends of the efferent branchial arteries and anastomosing with a
trunk of the subclavian artery may be comparable to the ves-
sels described by Miller (pp. 36 and 37) as epigastrische Arte-
rien, and the ventral artery or ramus epigastricus decendens of
Miller may be analogous to the mammaria interna of mammals.

3. Carotid Arteries.

The short common carotid arteries (Pl. I, figs. 1 and 5;
C.Car.A.) arise from the dorsal-cephalic corner of the first
efferent branchial arteries, and passing cephalad a short dis-
tance, about I cm., divide into the large external and internal
trunks.

(2). External Carotid or Carotts Posterior Artery (Pls. I
and II, figs. 1, 5 and 15; E.Car.A.). — This vessel at once
makes a dorsal-cephalic curve, passing through a foramen
formed by a lateral process of the prootic, in company with, but
directly below the jugular vein. Leaving this canal with the
infraorbitalis or truncus buccalis-maxillo mandibularis and
just ventrad and caudad of the external jugular vein, the exter-
nal carotid passes over the dorsal edge of the hyomandibular,
along the posterior border of the orbit, and then runs ventro-
caudad beneath the levator muscle of the palatine arch and the
adductor mandibulz muscles. It passes along the inner side of

52 ALLEN

the metapterygoid, and after receiving the hyoidean artery
comes to the outer surface through a foramen between the sym-
plectic, hyomandibular, preopercular, and quadrate bones.
This combined vessel, which may be designated as the mandzb-
ular artery (Pl. 1, fig. 1; Man.A), makes a sharp cephalic
bend, passing over the outer surface of the quadrate bone and
then curving inward around it to the inner surface of the man-
dible, where it terminates in 2 branches, which supply the ad-
ductor mandibule muscles. The main branch runs along the
inner dorsal surface of the bone, while the smaller branch sup-
plies the ventral portion of the muscles.

Along its ventro-cephalic course the external carotid sends
off many branches in the facial region and receives one. The
first vessel to be given off is the sclerotic-cr7s artery (P1. II,
fig. 15; Scl.Ir.A.). This rather small vessel arises from the
dorsal surface of the carotid immediately after it leaves the
canal formed by the prootic process. Close to its source the
sclerotic-iris artery gives off caudad the most anterzor cranial
cavity artery (Pl. II and III, figs. 15 and 24; C.C.A.), which
penetrates the skull through the middle and the largest of the
prootic foramina, along the dorsal surface of the roots of the
V nerve, and follows up the anterior surface of facialis portion
of the ramus lateralis accessorius to supply the adipose tissue
in the anterior portion of the cranial cavity. The main trunk,
however, continues cephalad ‘a short distance along the outer
surface of the prootic dorsad of the gasserian ganglion, and
here divides, one branch, the sclerotic artery (Pl. II, fig. 15;
Scl.A.) continues cephalad, but laterad to the truncus supra-
orbitalis or ramus ophthalmicus and the orbito-nasal vein.
When the orbit is reached, instead of curving inward around
the eye with the nerve and vein, it continues in a straight line
over the dorsal surface of the eyeball in company with the
sclerotic branch of the truncus supra-orbitalis and the sclerotic
vein, to supply the adipose tissue surrounding the dorsal surface
of the sclerotic coat. The other branch is the zv7s artery (Pls.
II and III, figs. 13, 15 and 19; Ir.A.), which enters the skull
through a foramen bounded by the dorsal process of the para-
sphenoid, the alisphenoid, and the prootic. Together with the

BLOOD-VASCULAR SYSTEM OF THE LORICATI 53

ciliary nerve and internal jugular vein it passes cephalad out
of the skull through the large olfactory-optic foramen, then
curving laterad in company with the ramus ciliaris longus and
the iris vein it crosses under the orbito-nasal vein and the trun-
cus supra-orbitalis, passing between the superior and external
rectus muscles, gives off a branch to the latter (Pl. II, figs. 13
and 15; Ex.R.A.). Then running laterad across the posterior
dorsal surface of the eyeball it penetrates the sclerotic coat in
its median line, and continuing laterad in the silver layer of the
choroid until the iris is reached, where, with the ramus ciliaris
longus, it bifurcates into 2 ventral vessels, which supply at
least the dorsal half of the iris. The normal arrangement of
the iris vessels is first the iris vein, then the ramus ciliaris lon-
gus, and finally the iris artery, but in several cases I have
observed the artery curving cephalad and passing between the
nerve and the vein.

The second vessel is given off a little below the sclerotic-iris
artery ; and after making a rather sharp caudal curve terminates
in the levator arcus palatini muscle. The next vessel is the
Sacialis-maxillaris artery (Pl. I, fig. 1; F.Max.A.) which arises
cephalad from the external carotid in the region of the orbit,
and passes obliquely over the external jugular vein and the ramus
mandibularis or the ramus maxillaris inferior, where it gives off
a large ventral branch, the faczal artery (Pl. I, fig. 1; F.A.),
for the adductor mandibule muscles. This branch runs along
the lateral surface of the deeper portion of the adductor mandi-
bulz, giving off numerous branches to the adductor muscles,
but does not follow the nerve to the mandible. The main por-
tion of the facialis-maxillaris artery proceeds along the floor of
the orbit in the adductor arcus palatini muscle, to which it gives
off numerous branches, and when the level of the nasal sac is
reached it receives a much larger artery from the orbzto-nasal
artery (Pls. Y and Wij-figs. 1 andi17; O.N.A.), which isa
branch of the internal carotid artery." This combined vessel
continues in a cephalic direction, supplying the region directly

1 McKenzie (52, p. 427) mentions the crossing of the branches of the ex-

ternal and internal carotids in the neighborhood of the nasal sac, in Amezurus
but nowhere have I met with the statement of their union.

54 ALLEN

behind the maxilla, and sends one branch ventro-caudad along
the outer ventral surface of the adductor mandibule muscle.
As the external carotid artery passes behind the metaptery-
goid it gives off the large pseudobranchial or afferent pseudo-
branchial artery (Pl. I, fig. 1; Ps.A.) caudad to the pseudo-
branchia. Passing behind the hyomandibular, the pseudo-
branchial artery gives off a good-sized vessel dorsad for the
levator muscle of the palatine arch, and shortly before the pseu-
dobranchia is reached the pseudobranchial artery bifurcates
into a short dorsal branch and a longer ventral branch. ‘These
vessels are analogous to the afferent branchial arteries of the
branchial arches. Like them they give off the nutrient pseudo-
branchial arteries, from which the nutrient filament arteries
arise for the pseudobranchial filaments (not shown in fig. 3.),
and at regular intervals an afferent pseudobranchial filament
artery (il. Li ig..35) a es Hilea.) 1S, given oft ‘to; the outer
margin of the filament, which is the side that lies closest to the
hyomandibular bone. As is the case in the branchial filament
this artery exhausts itself in numerous afferent cross-vessels,
which by dividing form the vessels from which the fseudo-
branchial filament network arises. ‘These cross-vessels are much
shorter than the corresponding branchial vessels and are about
80m apart, this being 20 more that the distance between 2
branchial filament cross-vessels. The longest septum of a
pseudobranchial filament and the inclosed capillary network is
much longer than the corresponding branchial septum, but the
network itself is much coarser. In alike manner the capillary
networks become collected into short cross-vessels on the inner
side of the filament, which unite in forming the efferent pseudo-
branchial filament vessels (P\. I, figs. 3 and 4; E.Ps.Fil.A).
These vessels terminate in, and form a short dorsal, and a longer
ventral artery, which lie immediately cephalad of the corres-
ponding afferent vessels, and are analogous to an efferent bran-
chial artery.’ They unite in forming the important ophthalmic
'The pseudobranch is a hemibranch or half-gill. Although its capillary net-
work is a trifle coarser than the network of a branchial filament and its afferent
vessel comes from the external carotid artery, still it has much in common with

a branchial filament. The septa containing the pseudobranchial capillaries are
exposed to the same current of water that bathes the gills, and it is natural to

BLOOD-VASCULAR SYSTEM OF THE LORICATI 55

or efferent pseudobranchial artery (Pls. I, II and II, figs. 1, 5,
I5, I9 and 20; Oph.A.), which supplies only the choroid coat
of the eye.” This vessel pursues a dorso-cephalic course, pas-
sing along the outer posterior edge of the levator arcus palatini
muscle to the parasphenoid bone; it then runs parallel to the
parasphenoid for a short distance, and when the anterior surface
of the dorsal parasphenoid process is reached, sends off a
branch inward in front of this process to anastomose with the
corresponding artery from the opposite side. Here the main
stem bends dorsad nearly encircling the orbito-nasal artery, and
passing between the inferior and internal rectus muscles in
company with the ramus ciliaris brevis and the ophthalmic vein
it follows along the posterior surface of the optic nerve, but be-
fore penetrating the sclerotic coat the artery makes a dorsal
curve around the ciliaris brevis and the ophthalmic vein, and
pierces the eyeball a little dorso-caudad of the optic nerve.
After passing through the silver layer of the choroid it bifur-
cates in the vascular layer of the choroid into an anterzor
choroid artery (Pl. Il, figs. 20 and 21; Chor.A.,) and a
shorter Posterior choroid artery (Pl. ILI, figs. 20 and 21: Chor.
A.@). These 2 vessels have somewhat the shape of a horse-
shoe, having its curved end dorsad and its open end ventrad.
Radiating from the outer surface of this horseshoe-shaped vessel
are numerous short vessels, which soon break up into smaller
vessels, and these in turn break up into minute parallel capil-
laries, forming the arterial retia mirabilia (Pl. III, figs. 19,
20 and 21; A.Ret.M.) of the so-called choroid gland or vaso-
ganglion, which has already been accurately described by Jones
(41), Miiller (50), Stannius (74) and Emery (24). Distally these
capillaries reunite, forming the chorozd arterzes proper (PI. III,
figs. 20 and 21; Chor.A.), which supply the choroid with
arterial blood. A section through the choroid and retina (Pl.
III, fig. 21) shows us that the choroid vessels are arranged in
suppose that the arterial blood which passes through these filaments receives
additional oxygen from the water.

2T have made several separate injections of the ophthalmic artery, cephalad,
after it leaves the pseudobranchia to see if it had any connection with the other

arteries, especially the orbitonasal artery with which it comes in such close con-
tact; but no connection whatever was found.

56 ALLEN

2 layers; an outer layer of large arteries and veins, and an
inner layer of capillaries. The capillary layer is separated
from the retina only by the thin pigment layer of the choroid.
A little dorsad to the point of union of the hyoidean artery
with the external carotid, the latter sends off, caudad, a smaller
posterior hyoidean artery (P1. 1, fig. 1; P.Hyo.A.). Close to
its point of origin this vessel gives off a dorsal branch, which
runs in front of the preopercular and directly behind the ramus
mandibularis VII, supplying the inner side of the deeper
adductor mandibule muscle. Passing ventro-caudad through
the same foramen as the hyoidean artery it runs parallel with
it. In its course along the inner side of the preopercular it
passes along the dorsal surface of the interhyal a little below
the hyoidean vein; then curving around the ventral edge of the
epihyal it comes to lie above the vein, finally terminating in
several vessels to the hyohyoideus superior muscle in the region
of the last branchiostegal ray.
(6) Lnuternal Carotid or Carotis Anterior Artery (Pl. I, figs.
1 and 5; I.Car.A.).— This vessel after leaving the common
carotid bends inward, passes ventrad across the jugular vein to
penetrate the internal carotid foramen (a foramen formed by the
dorsal process of the parasphenoid, the parasphenoid, and the
prootic bones) into the eye-muscle canal. Here it divides into
a cephalic and a horizontal trunk. The former is the orbito-
nasal artery, and the latter unites in the median line, above the
parasphenoid, with the corresponding trunk from the opposite
side, the combined trunk being the encephalic or brain artery.
The encephalic or brain artery (Pls. I, II and III, figs. 1,
5, 15, 23 and 25; Enc.A.) proceeds dorsad between the
external recti muscles and penetrating the floor of the brain
case directly cephalad of the hypophysis, and exhausts itself in
4 branches, which are given off at right angles to one another.
The cephalic one may be designated as the anterior cerebral
artery, the lateral ones as the right and left posterior cerebral
arteries, and the small posterior one as the infundibular artery.
Soon after leaving the main stem the anterior cerebral artery
(Pl. III, figs. 23 and 25; A.Cer.A.) divides; the 2 branches
running parallel for a short distance in a sort of zig-zag course

BLOOD-VASCULAR SYSTEM OF THE LORICATI Wl

along the ventral surface of the left optic nerve, and shortly
before the olfactory lobes are reached they bear off laterad
around the optic nerves, but, before leaving them, each vessel
gives off a branch, which continues along the ventral surface
of the nerve to the eye. This is the oftcc or retina artery (Pl.
Ill, figs. 22, 23, and 25; Opt.A.), which gives off branches to
the nerve and finally penetrates the eye-ball a little cephalad of
the nerve. Once inside the retina it continues along the retina
fissure (see fig. 22), giving off branches to either side and
especially to a whitish gland-like body situated on the side of
the fissure close to the falciform process. The main portion of
the artery, however, breaks up on the falciform process, the
campanula Halleri, and even extends over on the lens. It is
also probable that the retina receives nourishment from the
choroid arteries, which are separated from the retina only by
the thin pigment layer of the choroid. The main anterior cere-
bral artery after curving around the optic nerve divides into an
anterior and a posterior portion. Close to the point of bifurca-
tion the anterior branch sends forward a small vessel, which
runs along the ventral surface of the olfactory nerve, but the
main trunk passes inward and anastomoses with its fellow in
the median line. This point of union marks the source of 2
vessels, a smaller dorsal one designated as the most anterior
cranial cavity artery (Pi. Ill, fig. 23; C.C.A.), coming up
between the olfactory lobes to supply the adipose tissue in the
anterior region of the cranial cavity and a larger caudal vessel,
which runs in a median line between the optic nerves and the
cerebral hemispheres, giving off several branches to the latter
through the median fissure. The posterior branch of the
anterior cerebral artery is a superficial vessel; it follows caudad
along the ventro-lateral surface of the cerebrum, passing between
it and the optic nerves, and giving off superficial branches to
the ventral surface of the cerebrum and the anterior surface of
the mesencephal. Sometimes the right, but more often the left
artery continues dorsad with the epiphysis as the second cranzal
cacy artery (laine) 2301. BANS):

The posterior cerebral arterzes (P\. III, figs. 23 and 25; P.-
Cer.A.) come off from the encephalic artery at right angles to

58 ALLEN

the anterior cerebral artery; they run ventro-laterad across the
optic nerves, the cerebral hemispheres, the III and IV nerves.
Shortly after crossing the IV nerve each vessel makes a sharp
curve at nearly right angles; then passing caudad between the
IV nerve and the roots of the V and VII, parallel with, but
inside of the corresponding vein, they give off several super
ficial branches to the mesencephal (optic lobes) and hypoaria
(inferior lobes). The outer layer of the former contains a mass
of blood vessels. Close to the posterior end of the hypoaria
each posterior cerebral artery bends inward with the III nerve
and the corresponding vein, between the mesencephal, hypoaria
and crura cerebri, and when the saccus vasculosus is reached
this vessel divides into an anterior and a posterior branch. The
anterior branch unites with the corresponding vessel from the
opposite side in the median line above the anterior part of the
saccus vasculosus to form the mesencephalic artery (P1. III, fig.
25; Me.A.), which passes cephalad a short distance in the
crura; then turning dorsad, penetrates the floor of the mesen-
cephal directly in front of the valvula cerebelli (volvula of
other authors), and here sends out a lateral branch along the
dorsal surface of each torus semicircularis. In like manner
the posterior forks of the posterior cerebral arteries unite in the
median line above the posterior end of the saccus vasculosus,
and the vessel thus formed continues caudad along the ventral
surface of the oblongata as the myelonal or oblongata artery
(Pl. Ill, figs. 23 and 25; My-.A.). Along its short course
several branches are given off to the oblongata and one to the
auditory region. ‘The first vessel for the oblongata is given off
near the source of the myelonal artery and passes up through
the crura to the metaccele (IV ventricle), where it branches out
caudad in the dorsal part of the crura. The second branch
comes up through the ventral fissure of the oblongata in the
neighborhood of the facialis lobe and breaks up similarly to the
first branch. The third branch, which is much larger, is the
auditory artery (Pl. III, figs. 23, 23a, 24 and 25; Aud.A.).
Its course is obliquely laterad across the oblongata, but before
coming out from under the roots of the VII nerve, sends up a
dorsal branch, the ¢hzrd cranial cavity artery (P\. II, figs. 23

BLOOD-VASCULAR SYSTEM OF THE LORICATI 59

and 23a; C./’C.’A.’’), which passes between the ventral later-
alis and the motor roots of the VII nerve to the roof of the
skull, supplying the adipose tissue surrounding the brain and
the semicircular canals. Emerging from beneath the motor
root of the VII nerve, the auditory artery divides into an ante-
rior and a posterior auditory artery. The anterzor auditory
artery (Pl. Ill, figs. 23@ and 25; A.Aud.A.) follows along
the anterior surface of the ramulus acusticus ampulle ante-
rioris; passing beneath the anterior ampulla to which it gives
off a branch, it continues on to the external ampulla and its
semicircular canal. The posterzor auditory artery (Pl. III,
figs. 23, 23@ and 25; P.Aud.A.), which at first passes caudad
under the ramulus acusticus ampulle anterioris and the ramulus
acusticus sacculi, comes up through the center of the latter and
passes along in front of the ramulus acusticus ampulle poste-
rioris, to supply the posterior ampulla, its semicircular canal,
and the utriculus. The myelonal artery terminates in 2 forks
on the ventral surface of the myel, in the region of the first
spinal nerves. These branches usually anastomose with a
branch of the first neural or vertebral arteries, which having
their origin from the subclavians make them analogous to the
anastomosis of the basilar and vertebral arteries of mammals,
of which a more detailed description will be given under the
subclavian arteries. At the point where the posterior cerebral
artery bends to penetrate the mesencephalon it gives off, caudad,
the cerebellum artery (Pl. Ill, figs. 23 and 24; Cer.A.). This
vessel continues parallel, but above the IV nerve, ventrad to
the optic lobes, and laterad to the crus. In its caudal course
it gradually rises higher on the crus, until in the region of the
posterior end of the optic lobes it gets to lie between the optic
lobes and the valvula cerebelli. A little behind the origin of
the IV nerve and the posterior end of the optic lobes this vessel
penetrates the dorso-lateral wall of the valvula cerebelli at the
point where the molecular layer of the valvula unites with the
corresponding layer of the cerebellum. Its course is then
caudad a little to one side of the median line, gradually ex-
hausting itself in the granular layer of the cerebellum.

The fourth and smallest vessel to be given off from the en-

60 ALLEN

cephalic artery is the zzfundibular artery (Pl. III, fig. 25; Inf.-
A.). This vessel, which is given off caudad to the hypophysis
and infundibulum, sometimes arises from either of the pos-
terior cerebral arteries close to their origin from the encephalic
artery.

Orbito-nasal Arterzes (Pls. I, II and III, figs. 1, 5, 13, 17
and 18; O:N.A.).— These vessels which are the cephalic
branches of the internal carotid arteries, pass forward along
the dorso-lateral surface of the parasphenoid. While still within
the eye-muscle canal each orbito-nasal artery runs below the
recti muscles, giving off several small branches to the superior,
inferior, and internal recti muscles. Shortly after reaching
the orbit, what I have designated as the rectus artery (Pl. I,
fig. 13; Rec.A.) arises between the internal and the inferior
recti muscles, giving off at first a small branch to the outer
surface of the internal rectus muscle; then dividing, one branch
continues caudad between the external and internal recti mus-
cles; while the other branch curves laterad a short distance
and in turn bifurcates, one branch going dorsad to the superior
rectus muscle, and the other to the inferior rectus muscle. The
main orbito-nasal trunk, continuing cephalad, passes behind
the internal rectus muscle to which it sends several vessels;
and in the anterior part of the orbit passes between, but lat-
erad to the oblique muscles, giving off a dorsal branch to
the superior oblique muscle, and in the specimen from which
fig. 13 was drawn, 2 ventral branches for the inferior ob-
lique muscle. As has already been mentioned, the blood
supply for the external rectus muscle comes largely from the
iris artery, which is a branch of the external carotid artery.
Together with the orbito-nasal vein and the olfactory nerve,
the orbito-nasal artery passes out of the orbit through the olfac-
tory foramen in the prefrontal bone. In passing through this
foramen and cephalad of it, the vein lies mesad of the nerve,
and the artery lies ventrad to both vein and nerve. Soon after
leaving the orbit the orbito-nasal artery gives off at least 2
dorso-cephalic vessels, the xasal sac arterzes (Pl. II, figs. 17
and 18; N.S.A..,)). These small vessels at first pass behind and
above the olfactory nerve to supply the dorsal radial filaments

BLOOD-VASCULAR SYSTEM OF THE LORICATI 61

of the nasal sac. They penetrate the base of the filaments
with branches of the olfactory nerve, and running through the
inner connective tissue layer send off branches into the secon-
dary or branching filaments. The main orbito-nasal trunk
after passing behind the nasal sac with the corresponding vein
and the olfactory nerve divides into a cephalic and a ventral
branch. The smaller cephalic branch, crossing behind the or-
bito-nasal vein, proceeds above it, and becomes the mawzlla
Gren (eis lands li, nes? 1.17 and 13; Max:A. 7.) Ehis
artery in turn also breaks up into 2 vessels; a dorsal one, which
penetrates the premaxilla; and a ventral one, which runs along
the posterior surface of the premaxilla. The larger ventral
branch is the fostertor maxilla artery (Pls. I and III, figs. 1, 17
and 18; Max.A.,)); at the ventral edge of the nasal sac it sends
a branch inward to the palatine arch; and directly below this
branch at least 2 ventral nasal sac artertes (PI. Ill, fig. 17;
N.S.A.,,)) are given off dorsad, which supply the ventral fila-
ments in a like manner to dorsal nasal sac arteries. Then an-
astomosing with the much smaller facialis-maxillaris artery it
runs along and breaks upon the outer surface of the adductor
mandibulz muscle, immediately behind the maxilla.

(c) Summary of the Carotids. — Parker has well said (60, P.
653), that: ‘*The application of the name ‘carotid’ to the ce-
phalic arteries of fishes must of course be taken to imply nothing
more than a general correspondence with the similarly named
vessels in the higher Vertebrata.” For example, his anterior
carotid (internal carotid) in M/uste/us (60, fig. 6), and the similar
artery in Hydrolagus, Chimera (PI. III, fig. 26; I.Car.A.), are
almost analogous to the ophthalmic artery of Ophzodon (PYvis
figs. 1and5 ; Oph.A) provided that it anastomosed with the orbito-
nasal artery with which it comes in such close contact. In the
same connection, Parker proposes to substitute the names ante-
rior and posterior carotids for the internal and external carot-
ids. This substitution may seem advisable in the Selachians,
where the carotids at first occupy a distinctly anterior and pos-
terior position ; but in the case of the Teleosts that I have exam-
ined the vessel which has been designated as the internal car-
otid has a distinctly profundus course, and the external carotid

62 ALLEN

a superficial one. Even though the cephalic portion of the
internal carotid crosses the tract of the external carotid and a
branch of one anastomoses with a branch of the other, still, in
the main, the internal carotid supplies the region of the internal
carotids of the Mammalia. It certainly extends no farther
cephalad than the exteral carotids. For these reasons, in
Ophiodon, it seems advisable {to retain {the names internal and
external.

4. Opercular and Dorsal Branchial Muscle Arteries.

These vessels are 2 very constant arteries, which arise from
the dorsal part of the second efferent branchial artery.

Of the, thevopercular artery (P\.1, fis. 1;.Op.A.) asthe
most dorsal and cephalic vessel. It arises from the anterior
surface of the second efferent branchial artery near its point of
union with the first efferent branchial artery; its course is first
cephalad for a short distance, passing over the second obliquus
dorsalis muscle, to which it gives a branch; then curving dor-
sad, sends off a cephalic branch, which supplies the first inter-
nal branchial levator muscle (Levatores arcuum branchialium in-
terni of Vetter) and the first obliquus dorsalis muscle; and a little
farther up, a third artery is given off to the 4 outer branchial
levator muscles (Levatores arcuum branchialium externi of
Vetter). Then continuing dorsad, laterad to the first efferent
branchial artery and jugular vein, it sends off a caudal branch
to the levator operculi muscle of Vetter, and when the level of
the opercular is reached, terminates by running ventrad along
the inner surface of this bone.

The vessel, which is designated as the dorsal branchial mus-
cle artery (Pl. 1, fig. 1; Br.M.A.), but which supplies fewer
branchial muscles than the one designated as the opercular
artery, arises from the posterior surface of the second efferent
branchial artery directly below the opercular artery. Its course
is caudad, passing behind the second internal branchial levator
muscle, and over the third and fourth obliqui dorsales muscles,
it sends off a branch to each. Then after crossing over the
fourth efferent branchial artery it curves ventrad, supplying the
occipito-clavicularis muscle, the pharynx, and the dorsal part of
the pharyngo-clavicularis internus muscle.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 63

5. Subclavian Arteries.

The subclavian artertes (Pls. I and II, figs. 1, 5, 14 and 16;
Sub.A.), usually,’ have their origin in a single trunk from the
common chamber (fig. 5, C.C.). This common subclavian
trunk (Pl. I, fig. 5) arises above and between the dorsal
aorta and the cceliaco-mesenteric artery. For a short dis-
tance it runs parallel to the aorta and the cceliaco-mesenteric
artery, and then branches at nearly right angles; the right
subclavian passing obliquely above the cceliaco-mesenteric
artery, the right dorsal branchial retractor muscle, and the
right head kidney to the right pectoral fin; while the left sub-
clavian passes between the aorta and the cceliaco-mesenteric
artery, above the left dorsal branchial retractor muscle and left
head kidney to the left pectoral fin.

After crossing the head kidney the course of each subclavian
is ventrad, passing with the combined trunk of the first and
second spinal nerves across the outer surface of the head kidney
and cardinal vein to the inner surface of the pectoral fin. In
the region of the dorso-lateral edge of the head kidney the sub-
clavian gives off the frst neural artery (Pls. I and II, figs. 1
and 16; Neu.A.,,), which is somewhat analogous to the verte-
bral artery in mammals. This vessel runs obliquely dorsad in
front of the combined trunk of the first and second spinal
nerves, and then passes over the second and first epibranchial
arteries, but behind the thymus gland. When the atlas is
reached it gives off the first sp/nal or myelon artery (P1. Il,
fig. 16; Sp.’A.’), which enters a foramen in the exoccipital
and usually anastomoses with the myelonal artery. The main
stem, however, continues dorsad, terminating in a cephalic,
and a dorsal branch. The cephalic branch supplies the
trapezius muscle and sends a branch ventrad, which probably
supplies the thymus gland. This small vessel I have been
able to trace to the thymus, but never have seen it penetrate the
gland. Strange to say the arterial supply for the thymus is
more difficult to trace than the venous system. The dorsal
branch of the first neural artery is destined to supply the super-
ficial, the levator, and the depressor muscles of the first dorsal

1For exception see page 45.

64 ALLEN

spine; and in the specimen from which fig. 16 was drawn, the
levator muscle of the second dorsal spine, as well as sending up
a branch behind the first dorsal spine.

After giving off the first neural artery the subclavian might
be designated as the brachial artery as in mammals, but it
seems hardly advisable to press such homologies. Emerging
from the head kidney the subclavian passes ventrad along the
inner anterior surface of the pectoral superficial adductor mus-
cle; and when the pectoral profundus adductor muscle is
reached, a branch is given off to the superficial muscle; then
bifurcating, forms what I have designated as the external and
internal subclavians.' The zxternal subclavian artery (P|. Il,
fig. 14; I.Sub.A.) for a short distance continues along the
inner cephalic edge of the superficial adductor muscle; then
divides into a superjfictal internal subclavian artery (P1. Il, fig.
14; I.Sub.A.,,), which after giving off a few branches to the
superficial adductor muscle continues obliquely ventrad along
the inner surface of the profundus adductor muscle; and a pro-
Jundus internal subclavian artery (Pl. Il, fig. 14; I.Sub.A..,),
which immediately penetrates both superficial and profundus
adductor muscles and runs obliquely ventrad between the pro-
fundus muscle and the scapula, giving off several branches to
the former. In the neighborhood of the most dorsal pectoral
ray this vessel divides into a brachial ossicle artery and a pec-
toral fin artery. The brachial ossicle artery crosses these bones
in its ventral course just back of the pectoral rays, and ex-
hausts itself by giving off vessels to the distal part of the pro-
fundus muscle and by sending off branches between the ossi-
cles to the profundus muscle on the outside of the shoulder-
girdle. While the pectoral fin artery penetrates the basal canal
(see note, page 50) between the first, or most dorsal, and the
second rays, and continuing ventrad in this canal anastomoses
with the hypobranchial artery. Throughout its entire course
it gives off a branch to the central canal of each ray, which
soon divides, one branch continuing along the dorsal side of the
cavity and the other along the ventral side. The external sub-
clavian artery (Pl. Il, fig. 14; E.Sub.A.) immediately passes

'Perhaps external and internal pectoral arteries would be better names.

BLOOD-VASCULAR SYSTEM OF THE LORICATI . 65

through the scapula foramen with the external subclavian vein
and a branch of the first and second spinal nerves, and then
runs obliquely ventrad between the superficial and profundus
abductor muscles, giving off several branches to each.

6. Caliaco-Mesenteric Artery.

The celiaco-mesenteric artery (Pl. I, figs. 1 and 5; Ce-
Mes.A.), which is destined to supply the entire viscera
with the exception of the kidney, urinary-bladder, and repro-
ductive organs, is in itself arather short vessel. With the
subclavian it has its source in the common chamber (PI. I,
fig. 5; C.C.) beneath and to the right of the aorta and sub-
clavians. It pursues a ventro-caudal course, and passing
between the inner side of the right fork of the kidney and the
right dorsal branchial retractor muscle enters the thoracic
cavity, where it soon divides into the cceliac and mesenteric
trunks.

(a) Celiac Artery (P\. I, figs. 1,6 and 11; Co.A.).— This
large vessel for a short distance, runs parallel, but cephalad to
the mesenteric artery, then curving around under the stomach,
supplies the liver, ventral part of the stomach, pyloric ceca,
and a part of the posterior end of the intestine.

The first branch to be given off from the ceeliac is the left
hepauc artery (Pi. 1, figs. 6 and 115 \L.Hep.A.). It leaves
the cceliac under the stomach and breaks up into as many
branches as there are terminal branches of the left portal vein.
These branches are somewhat irregular, but the first and most
cephalic one accompanies terminal branch (a) of the left portal
vein. Usually this branch is the source of the posterzor gall-
bladder artery (Pl. I, fig. 11; P.G.Bl.A.), which runs along
the dorsal surface of the gall-bladder and anastomoses with the
anterior gall-bladder artery, which is a branch of the right
hepatic artery (a branch of the mesenteric artery). Both gall-
bladder arteries break up into a minute capillary system on the
surface of the gall-bladder. A minor posterior gall-bladder
artery is often given off to the ventral surface of the gall-
bladder (see fig. 11). The second branch of the left hepatic
artery accompanies terminal branch (6) of the left portal vein

Proc. Wash. Acad. Sci., June, 1905.

66 ALLEN

and the remaining branches follow terminal branches (c), (@)
and (e). Ordinarily 1 or 2 branches from the last mentioned
arteries follow along in the gastro-hepatic omentum to supply
the ventral portion of the stomach. All of the branches of the
left hepatic artery follow their corresponding venous trunks to
their terminal endings in the substance of the liver. The left
hepatic artery furnishes the principal arterial supply for the
liver, but in some specimens an additional fosterzor or mz¢nor
left hepatic artery (Pl. I, fig. 11; L.Hep.A.,,)) arises from the
ceeliac a little farther caudad than the main left hepatic artery
and anastomoses with the posterior branches of the left hepatic
vessel. Beside the left hepatic vessels there is also the right
hepatic artery for the small right lobe of the liver, which will
be described further on under the mesenteric artery.
Continuing caudad, parallel, but to the right of the left
portal vein, the cceliac artery divides directly in front of the
pylorus into a right and left pyloric czca artery. One of
these forks (usually the right) is always considerably longer
than the other. The right pyloric ceca artery( Pl. I, figs. 1 and
6; R.Cze.A.) passes at least two-thirds around the pylorus, in-
side of the pyloric ceca vein a little above the ceca, and in its
course gives off at least 3 branches to the ceca. Within the
ceca the larger vessels run in the muscular coats and break up
into a capillary network in the connective tissue layer of the
crypts as in the intestine. One branch of the right pyloric
ceca artery is sent off to the pylorus and 2 rather large pos-
terior gastric arteries are given off to the posterior or cardiac
portion of the stomach. From the 77ght posterior gastric ar-
tery (fig. 1; R.P.Gas.A.) one or more branches run along in
the peritoneal fold over the ceca to anastomose with the intes-
tinal branch of the mesenteric artery. The left pyloric ceca
artery, which is usually much smaller than the right, pursues
a similar course on the left side of the pylorus, giving off 2 or
3 branches to the ceca and one to the pylorus. When this is
the smaller of the 2 ceca arteries, no branches are given off
from it to the posterior end of the stomach, however, only in

about one case in Io is the left pyloric ceca artery larger than
the right.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 67

Quite an important vessel arises from the right side of the
coeliac artery shortly before it separates to form the pyloric caca
arteries, or sometimes it may arise from the right pyloric ceca
artery; it is the vessel designated as zntestznal artery,,, (Pl. I,
figs. 1, 6 and 11; Int.A..)), which strikes the intestine about
mid-way between the pylorus and the rectum. For a short
distance it runs along, inclosed in adipose tissue, just dorsad of
the intestine, and crossing over to the ventral side of the intes-
tine, exchanges places with intestinal artery,,. This vessel is
distinctly a posterior intestinal artery and usually extends to
the rectum. Throughout its entire course it sends off branches
to the muscular walls of the intestine, which break up into a
capillary network in the connective tissue layer of the crypts.
In the region of the liver several small branches from the ce-
liac are given off to the anterior part of the intestine.

(6) Mesenteric Artery (Pl. I, fig.1; Mes.A.). — This vessel
is destined to supply the spleen, the greater part of the stomach,
and intestine. Soonafter leaving the cceliaco-mesenteric trunk
the mesenteric artery gives off the /e/¢ gastric artery (P1. 1, figs.
1 and 6; L.Gas.A.) to the left and ventral side of the stomach.
This vessel, which lies above the corresponding vein and left
gastric ramus of the vagus nerve, crosses the stomach at right
angles, then passing along the left side of the stomach, gives
off branches to either side, which soon penetrate the muscular
walls and break up into a capillary network in the connective
tissue layer of the crypts. The main mesenteric trunk after
following the stomach for a short distance bifurcates into the
right gastric, and intestinal artery,,. The rzght gastric artery
(fig. 1; R.Gas.A.), which is considerably larger than the left,
continues between the right gastric ramus of the vagus nerve
and the right gastric vein to the posterior or cardiac portion of
the stomach, giving off branches from either side to the mus-
cular walls of the stomach. Close to its origin it sends off a
branch to the right (see fig. 1), which crosses the cceliac artery
and the right portal vein to a gland-like body (G. fig. 1) situ-
ated at the junction of the right gastric and the intestinal veins
(in structure this gland is very much like the suprarenal bodies).
ihe /ntesinalantery i Pil, hes.) Band) Ose into...) pur

68 ALLEN

sues a general caudal direction. Close to its origin this vessel
gives off the right hepatic artery (Pl. I, fig. 11; R.Hep.-
A.), which supplies the smaller right lobe of the liver. This
branch runs along by the side of the right portal vein and
midway between its source and the right lobe of the liver sends
off the anterior gall-bladder artery (P\.1, fig. 11; A.G.BI.A.).,
which breaks up on the anterior surface of the gall-bladder, and
as has already been mentioned under the head of the posterior
gall-bladder artery, the 2 gall-bladder arteries anastomose on
the surface of the bladder. A little farther caudad, the anterzor
intestinal or duodenum artery (fig. 1; A.Int.A.), is given off
from the intestinal artery to the anterior loop of the intestine.
The main intestinal trunk then sends off the rather large sflenzc
artery (Pl. I, figs. 1 and 6; Spl.A.), which penetrates the
anterior surface of the spleen, together with, but dorsad of the
splenic vein. Once inside the spleen, it runs entirely through
the organ, branching out in the shape of a fan. The intestinal
artery, curving around the dorsal surface of the spleen runs
along in adipose tissue, parallel with, but closer to the intestine
than the corresponding intestinal vein. This artery varies
greatly inlength. Usually, however, it continues to the rectum,
receiving anastomotic branches from the right posterior gastric
artery, and curving around to the opposite or dorsal side of the
intestine, anastomoses with the posterior mesenteric artery (fig.
1; P.Mes.A.). In several specimens, however, the intestinal
artery did not continue much farther caudad than the spleen,
and the posterior part of the intestine usually supplied by this
vessel received its supply from the right posterior gastric artery
and the posterior mesenteric artery. As in the stomach and
ceeca, the larger vessels run in the longitudinal and circular
muscular coats and break up into a network of capillaries in
the connective tissue coat.

(c) Comparisons with Other Genera of the Suborder.—In
different genera, it is within the viscera where most of the vari-
ation in the blood vessels occur. This is perhaps in a large
measure due to the variation in the shape and location of the
various organs and to the presence or absence of certain of them.
Of the 3 fishes figured in plate IV, probably the arterial

BLOOD-VASCULAR SYSTEM OF THE LORICATI 69

supply for the viscera of Scorpenichthys is most like Ophiodon,
and Sebastodes most like the ordinary Acanthopterygian fishes.

The origin of the cceliaco-mesenteric trunk is the same for all
4 genera studied, but as regards the branching of the cceliac
and especially the mesenteric, there is considerable variation.

Celiac Artery. —In Hexagrammos the ceeliac branches off
from the cceliaco-mesenteric trunk much further caudad than is
the case with the other 3 genera; in fact, the cceliac and the
left gastric are given off together. In all 4 genera the cceliac
terminates by dividing into the 2 pyloric ceca arteries, but in
Ophiodon only does a pyloric ceca artery supply the posterior
part of the stomach. In Sedastodes the left hepatic arteries
(Pl. IV, fig. 32: L.Hep.A.) arise in a similar manner to
the corresponding vessels of Ophzodon, except that the pos-
terior left hepatic artery is much larger than in Ophzodon ; while
in Scorpentchthys and Hexagrammos, strange to say, the left
hepatic arises from the right gastric, but in Hexagrammos it
comes into such close contact with the cceliac that at first one
might be led to believe it arose from the cceliac or at least anas-
tomosed with it. In Hexagrammos only does the intestinal
artery.) arise from the ceeliac as in Ophzodon; in Scorpenich-
thys and Sebastodes it is a branch from intestinal artery,,).

Mesenteric Artery. —The right and left gastric arteries
respectively are essentially the same in all 4 genera. How-
ever, since there are so many variations in the branching of the
right gastric, the distribution of intestinal artery,,,, and the addi-
tional air-bladder and anterior spermatic arteries in Sebastodes,
it seems advisable to describe in detail the distribution of the
mesenteric artery for each of the above genera.

Mesenteric Artery in Scorpenichthys (P1. IV, fig. 29; a fork
of Coe. Mes.A.).— After giving off the left gastric artery, the
mesenteric artery separates into the r7ght gastric artery (fig.
29, R.Gas.A.) and the intestinal artery,,,(fig. 29; Int.A.,)). The
former gives off the left hepatic artery (figs. 29 and 30; L.-
Hep.A.) and the latter follows along the stomach for a short
distance, giving off a small branch to a smal] gland-like body,
marked g, and the sflenzc artery (Pl. IV, fig. 29; Spl.A.), but
before entering the spleen this vessel sends off a Posterior gas-

70 ALLEN,

tric artery (Pl. IV, fig. 29; P-Gas.A.), which supplies the
ventral posterior or cardiac portion of the stomach. The main
intestinal trunk crosses the ceca and after passing under the
first arm of the ileum sends off ¢ntesténal artery,s (Pl. IV, fig.29 ;
Int A.,), which supplies the posterior part of the intestine; while
the main intestinal trunk continues caudad, supplying both arms
of the ileum. Except from the different points of origin, the
left hepatic artery (P\. IV, figs. 29 and 30; L.Hep.A.) coming
from the right gastric artery, and the r7ght hepatic artery (Pl.
IV, figs. 29 and 30; R.Hep.A.) from the left gastric artery,
the peripheral distribution of the 2 hepatic arteries is practically
the same as in Ophiodon. Perhaps it should be mentioned that
there is but one left hepatic artery in Scorpenzchihys.
Mesenteric Artery in Hexagrammos (P|. IV, fig. 27; Mes.-
A.).— As has already been stated, the left gastric artery (Pl.
IV, fig. 27; L.Gas.A.), which is much shorter than in the other
3 genera, is given off almost directly opposite the cceliac artery.
This would make it appear as though the cceliaco-mesenteric
trunk separated into 3 branches, namely, the cceliac, mesenteric
and left gastric arteries. ‘The mesenteric artery runs along the
stomach for a short distance and divides into the characteristic
right gastric and intestinal arteries. As in Ophiodon the right
gastric artery (Pl. IV, fig. 27; R.Gas.A.) follows along the
right and upper side of the stomach, but it has, however, ex-
changed positions with the right gastric vein. In this respect
it also differs from Scorpenichthys and Sebastodes. Close to
its source it gives off the left Aepatc artery (Pl. IV, figs. 27
and 28; L.Hep.A.), which comes into very close contact with
the cceliac artery and breaks up into 3 branches, which pene-
trate the liver with terminal branches @, 0, and ¢ of the left
portal vein. The branch following terminal branch @ anasto-
moses with the right hepatic artery in a similar manner to the
anastomosing of this branch of the left portal with the right
portal vein. As in Scorpenichthys there is but one left hepatic
artery. The Zntestinal artery, (Pl. IV, fig. 27; Int.A.,,) soon
after leaving the mesenteric artery sends off the r7ght hepatic
artery (Pl. IV, fig. 27; R.Hep.A.), which at first runs along the
surface of the gall-bladder as the gall-bladder artery, and pene-

BLOOD-VASCULAR SYSTEM OF THE LORICATI 7(al

trating the liver with the right portal vein, anastomoses with the
most anterior branch of the left hepaticartery. By this anasto-
mosis the conditions are somewhat analogous to Ophzodon;
where the posterior gall-bladder artery, which arises from the
most anterior branch of the left hepatic artery, anastomoses on
the surface of the gall-bladder with the anterior gall-bladder
artery, which is a branch from the right hepatic artery. The in-
testinal artery, then crosses above the anterior or duodenum
portion of the intestine and intestinal vein,,., gives off several
branches to the intestine and then continuing caudad with the
intestinal vein,,, between the arms of the iliac loop, extends past
the loop to supply the rectum. When near the end of the loop
the splenic artery (Pl. IV, fig. 27; Spl.A.) is given off to the
spleen, which, strange to say, is located on the posterior end of
the intestine close to the rectum. However, before entering
the spleen, the splenic artery sends off a branch to the posterior
end of the intestine.

Mesenteric Artery in Sebastodes (Pl. IV, fig. 31; Mes. A.).
— In this genus, which is supposed to be less specialized than
the above genera, several new features are introduced, among
them, a vessel for the air-bladder and 2 for the reproductive
organs. After giving off the /eft gastric artery (P|. IV, fig.
31; L.Gas.A.), which is the principal artery for the stomach,
the mesenteric artery bifurcates into its 2 characteristic divisions,
namely, the right gastric, and intestinal artery,,. The rzght
gastric artery (fig. 31; R.Gas.A.) in Sedastodes is much shorter
than in the other 3 genera and gives off several important
trunks. The first important branch is the r7ght anterior sper-
matic artery (Pl. IV, fig. 31; R.Sper.A.). Together with the
corresponding vein this vessel passes caudad under the air-blad-
der vessels to supply the right ovary or testis with a large part
of its arterial blood, and anastomoses above with the spermatic
artery proper (fig. 31; Sper.A.). The second vessel to be
given off from the right gastric is the small 77ght hepatic ar-
tery (Pl. IV, fig. 31; R.Hep.A.). This vessel penetrates the
right lobe of the liver with the right portal vein, and often sends
off a branch to a gland-like body situated near the right portal
vein. Usually the right hepatic artery gives off the azterzor

72 ALLEN

gall-bladder artery (Pl. IV, fig. 34; A.G.BI.A.). In case
such a branch is given off it usually supplies the above men-
tioned gland (see fig. 34; G.) The third branch of the right
gastric is the azr-bladder retia mirabilia or anterior atr-bladder
artery (Pl. IV, fig. 31; A.BI.A.); it crosses above intestinal
artery,,, and the right anterior spermatic vessels, just in front of
the right mesenteric and the anterior air-bladder veins. Pene-
trating the thick ventral muscular walls of the air-bladder it
breaks up internally into small branches, which in turn break -
up into minute parallel arterial capillaries, that become contin-
uous distad with parallel venous capillaries, and which are
afterward collected into small veins that empty into the air-
bladder retia mirabilia vein. This sort of a horseshoe-shaped
mass of capillaries on the floor of the air-bladder is known as
the retia mirabilia or vaso-ganglion of the air-bladder; it is a
vaso-ganglion of the bipolar type. This broad expanse of
capillaries affords a good opportunity for the exchange of gases
from the blood to the bladder and conversely. ‘The fourth and
last branch to be given off from the right gastric artery is the
left anterior spermatic artery (Pl. IV, fig. 31; L.Sper.A.).
This vessel pursues a similar course to the right anterior sper-
matic artery, following parallel with the corresponding vein it
helps supply the left ovary or testis and anastomoses poste-
riorly with the spermatic artery proper. /ntestinal artery,,, (Pl.
IV, fig. 31; Int.A.,) pursues a general caudal course, passing
under or rather to the right of all the above mentioned arteries.

When in the neighborhood of the spleen it divides; the pos-
terior fork, which is designated as the continuation of the main
intestinal artery,,,, passes caudad to supply the posterior end of
the intestine; while the anterior fork soon divides into the
splenic artery and what I have designated as intestinal artery,,).
Intestinal artery, (Pl. IV, fig. 31; Int.A.,) is so named be-
cause it runs parallel with a vein, which has the same terminus
as intestinal vein ,,) of Ophzodon, but it is hardly probable that
this artery is homologous with intestinal artery,,, of Ophzodon.
This artery separates into an anterior branch, which supplies
the anterior part of the intestine or duodenum and a posterior
branch, which supplies the iliac part of the intestine. In some

BLOOD-VASCULAR SYSTEM OF THE LORICATI TS

specimens where there was no anterior gall-bladder artery, as
is shown in fig. 33, there is a postertor gall-bladder artery
(fig. 33; P.G.BI.A.) arising from the intestinal artery,,,, which
in addition to supplying the gall-bladder is continued caudad to
supply a portion ofthe ileum. The sPlenzc artery (Pl. IV, fig.
31; Spl.A.) penetrates the spleen with the splenic vein, but
before entering it, gives off a posterior gastric artery (P\. IV,
fig. 31; P.Gas.A.), which passes beneath the spleen to the
ventro-posterior end of the stomach; and like the posterior
gastric artery of Ofhzodon, which, however, has a different
origin, coming from the right pyloric ceca artery, it sends off
a branch to the posterior portion of the intestine.

4. Dorsal Aorta.

This vessel (Pl. I, figs. 1, 5, and ro D.Ao.), which is the
largest artery in a fish, arises as the most dorsal trunk from
the common chamber (Pl. I, fig. 5; C.C.) and continues
caudad in a median line directly below the vertebral column
to the last caudal vertebra. At first the dorsal aorta runs
between the 2 anterior lobes of the kidney, above and be-
tween the dorsal branchial retractor muscles, and when the
posterior unpaired part of the kidney is reached, runs along in
its dorsal groove. After leaving the kidney and the body
cavity, the aorta is known as the caudal artery (Pl. I, figs. 1,
7,8,9 and 10; Cau.A.). It penetrates the hemal canal of the
first caudal vertebra with the caudal vein and continues in the
hzmal canal above the vein until the last caudal vertebra is
reached, where at about the middle of the last centrum it
separates into a right and a left caudal artery. The /e/t cau-
dal ariery, (El) Mito. 18 5, Cav.A..) is) much the ‘shorten;
it sends a branch upward in front of the urostyle, which sup-
plies both profundus and superficial muscles. The much
larger right caudal artery (Pl. I, figs. 1 and 8; R.Cau.A.)
following along the outer margin of the last centrum and after
giving off a branch in front of the urostyle similar to the left
caudal artery, continues caudad in a median line between the 2
hypural bones, parallel with the longitudinal hemal lymphatic
vessel, giving off branches from both sides to the profundus

74 ALLEN |

muscle of the caudal fin. When the caudal fin is reached this
artery bifurcates into a dorsal and a ventral vessel, which run
dorsad or ventrad in the basal canal of the caudal rays, directly
in front of the corresponding lymphatic and venous vessels.
The central canal of each ray receives a branch, which at first
runs in the center of the cavity and then divides, the 2 forks
continuing caudad along the dorsal and ventral sides of the
canal.

Throughout its entire course the dorsal aorta gives off
branches to the great lateral muscles, the spinal cord, and the
rays of the unpaired fins; beside supplying the kidney, repro-
ductive organs and the rectum.

(a) Arteries Supplying the Great Lateral Muscle, Cord,
etc.—Perhaps the most typical place first to take up these ves-
sels is in the region of the caudal vertebre. In fig. 1 sucha
region is shown just posterior to the kidney. The common
arrangement consists of a dorsal or neural artery and a ventral
or hemal artery, which usually supply the region covered by
2 myotomes; sometimes, however, one of these arteries may
supply 3 or even 4 myotomes.

The dorsal or neural arteries (Pl. I, fig. 1; Neu.A.) in this
region arise from the dorsal side of the caudal artery. Emerg-
ing from the anterior surface of the hamal arch each neural
artery curves around the anterior end of either the right or left
side of the centrum. Here a branch, the medzan lateral artery
(fig. 1; M.Lat.A.) is given off to the great lateral muscle. A
second branch, the spznal or myelon artery, penetrates the spinal
foramen. The neural artery then curves around in front of
the neural spine and continues dorsad between the spine and
the neural lymphatic vessel. Near the end of the spine the
dorsal lateral artery (fig.1; D.Lat.A.) is given off to the great
lateral muscle. Then passing cephalad the neural artery sup-
plies the levator and depressor muscles of this and the preced-
ing dorsal rays, as well as supplying the superficial muscles
and sending up a branch behind this and the preceding dorsal
rays. This description will hold for all the neural arteries
from the head to the tail, except that the most cephalic one
arises from a different source (see under Subclavian artery),

BLOOD-VASCULAR SYSTEM OF THE LORICATI 75

and the second and third neural arteries (fig. 5; Neu.A.,,.3;)
supply the dorsal branchial retractor muscles and the anterior
forks of the kidney in addition to the musculature already
described.

Hemal Arteries (fig. 1; Hee.A.).—These vessels arise from
the ventral side of the caudal artery, a little behind the corre-
sponding neural arteries, and crossing over the caudal vein run
ventrad between the hemal spines and the hemal tymphatic
vessels. Near the end of the spines they give off the ventral
lateral artertes (fig. 1; V.Lat.A.) for the great lateral muscle,
then curving cephalad, break up among the superficial and
profundus anal ray muscles in like manner to the neural arteries
in the dorsal fin musculature. The homologous intercostal
arteries of the visceral body wall have their origin in a common
vessel, which supplies also the kidney and often the reproduc-
tive organs.

(6) Penal and Spermatic Artertes. — As has just been stated,
the renal and spermatic arteries as well as the intercostals often
have their source in one and the same artery, which is prob-
ably homologous with the hemal arteries of the caudal region.
For convenience we will speak of these common trunks in the
region of the anterior part of the kidney as the intercostal ar-
teries and in the region of the posterior part of the kidney,
where the main branch goes to the reproductive organs, as the
spermatic arteries.

Intercostal Arteries (fig. 1; Intc.A.).— These vessels arise
from the ventral side of the aorta, in the region of each alternate
vertebra, and passing across the lateral surface of either side
of the kidney, they give off several renal arterzes (igon ; Ken:
A.) for the kidney; but the main trunks or intercostal arteries
proper continue ventrad between 2 myotomes and anastomose
with branches from the ventral artery, the so-called ventral in-
tercostal arteries.

Spermatic Arterzes (Pl. I, figs. 1 and 10; Sper.A.).—In
both male and female there are at least 3 spermatic arteries,
which always cross the left side of the kidney, giving off
several renal arteries and one intercostal artery before leaving
the kidney for the reproductive organs. These arteries increase

76 ALLEN °

in size as these organs increase in size toward the breeding
season, which is in January at Monterey Bay. In the female
these vessels branch before reaching the ovaries and these
branches spread out over the outer and inner surfaces of the
ovaries; while in the male these branches penetrate directly
into the testes. No common spermatic artery is formed in
either male or female by the anastomosis of these branches, to
pass between and parallel with the reproductive organs, as is
the case with the veins. The anterior spermatic artery (PI. I,
figs. 1 and 10; Sper.A.,) arises from the ventral surface of the
aorta and passing obliquely ventrad across the left side of the
kidney, gives off 3 or 2 renal arteries for the kidney and an
intercostal artery, which passes ventrad between the 2 adjacent
myotomes; the main spermatic trunk also continues ventrad
to break up on the anterior surface of the ovaries or to pene-
trate the testes. The second spermatic artery (P1. I, figs. 1 and
10; Sper.A.,) is given off from the aorta, about the distance
of 2 vertebree from the first spermatic artery, and in like manner
sends off renal and intercostal arteries for the kidney and body-
wall; while the main trunk supplies the middle portion of the
ovaries or testes. The ¢hzrd or posterior spermatic artery (Pl.
I, figs. 1 and 10; Sper.A.,) is much the largest; in addition to
supplying the ordinary renal and intercostal arteries, it gives off
from 1 to 3 suprarenal arteries (Pl. 1, figs. 1 and 10; Sr.A.)
for that gland. In fig. 1 the third spermatic artery passed in
front of the gland and only one artery was observed to enter
the gland; while in fig. 10 the main artery passed behind the
gland and at least 3 arteries were seen to penetrate it. In the
specimen from which fig. 1 was drawn the fostertor mesenteric
artery (fig. 1; P.Mes.A.) arises from the last spermatic artery,
passing behind the posterior mesenteric vein, it continues ven-
trad with it between the ovaries to supply the rectum and anas-
tomoses with intestinal artery,,); while in the specimen from
which fig. 10 was drawn the posterior mesenteric artery was
given off much further dorsad and at first entered the kidney as
a renal artery; then passing ventrad between the testes with the
corresponding vein, supplied the rectum, but did not anastomose
with intestinal artery,,); while in still other specimens the pos-

BLOOD-VASCULAR SYSTEM OF THE LORICATI ii

terior mesenteric artery was not observed; possibly, however, it
was not injected. The posterior spermatic proper breaks up
into numerous branches, which run along the posterior surface
of the ovaries or penetrate the testes. The most posterior branch
of the third spermatic artery is destined to supply the common
oviduct or spermduct and sends off the antertor urinary
bladder artery to the bladder. The postertor urinary bladder
artery (Pl. I, figs. 1 and 10; Ur.B.A.) or the urinary bladder
artery proper arises from the aorta directly behind the kidney,
and in the specimen from which fig. 10 was drawn, a renal
artery was given off to the kidney. In addition to supplying
the urinary bladder this vessel usually sends off a branch to the
great lateral muscle. It is probably a modified hzemal artery.

(c) Comparisons of Hexagrammos, Scorpentchthys and Sebas-
todes. — In these 3 different genera there is not nearly as much
variation in the distribution of the dorsal aorta as there is in the
distribution of the cardinal veins. Hexagrammos is identical
with Ophiodon. In Scorpenichthys there are only 2 spermatic
arteries, but what has been designated as the urznary bladder
artery (P1. IV, fig. 29; Ur.Bl].A.) arises much farther cephalad
than the corresponding vessel in Ophzodon, and may in part be
homologous to the posterior spermatic artery of Ophodon,
except that it does not supply the reproductive organs; running
along the dorso-caudal surface of the kidney it passes between
the suprarenal bodies and sends off a branch to each of them.
(It will be noticed that the suprarenal glands are located much
further dorsad on the kidney than they are in Ofhzodon.).
Then passing ventrad the urinary bladder artery passes behind
the posterior mesenteric vein to supply the posterior part of the
urinary bladder, and usually it is continued still farther ventrad
to supply the rectum. In Sedastodes several changes are intro-
duced, which are caused by the presence of the air-bladder and
anterior spermatic arteries. Where the anterior spermatic artery
is given off in Ophiodon, Hexagrammos and Scorpenichthys a
similar vessel arises from the aorta in Sedastodes; this vessel,
however, is destined to supply the air-bladder and is designated
as the posterior atr-bladder artery (P1\. IV, fig. 31; P.A.BI.A.).
In passing over the left side of the kidney it gives off several

78 ALLEN

renal arteries and finally breaks up on the posterior end of the
air-bladder. The single spermatic artery (P1. IV, fig. 31; Sper.-
A.), which performs part of the function of the urinary bladder
artery of Ophzodon is given off from the aorta immediately in
front of the point where the caudal vein penetrates the kidney.
Near its source it sends off an intercostal artery (see fig. 31).
It then follows along the posterior margin of the kidney, to the
right of the caudal vein, and passing between the suprarenal
bodies,’ supplies each with a branch. The spermatic artery
then continues ventrad between the kidney and the reproduc-
tive organs, gives off caudad the wrznary bladder artery (fig.
31, Ur.Bl.A.), which is the only artery observed for the bladder.
When the genital organs are reached, the spermatic artery
anastomoses with the 2 anterior spermatic arteries already de-
scribed under the head of the mesenteric artery.

VII. PERIPHERAL DISTRIBUTION OF THE VEINS.

The veins in general follow their corresponding arterial
trunks, but not so closely as they do the nerves. There is
much less literature on the veins than on the arteries. In Se-
lachians where it is so much more difficult to inject the veins
this is not strange, but with the Teleosts no more difficulty is
experienced in injecting the veins. Generally the whole venous
system can be satisfactorily injected from one point. (See
under paragraph on technique).

1. fugular Vetns.

These large sinus-like vessels (Pls. I and II, figs. 1, 5, 15
and 16; J.V.), which are much longer than the corresponding
common carotid arteries, arise in front of the prootic process
from 3 principal trunks (see fig. 15). The external jugulars,
coming from the facial region; the internal jugulars, coming
from the eye, eye-muscles, and brain; and the orbito-nasal
vein. Each jugular immediately enters the foramen formed
by the prootic process and in its course through this foramen it
is a rather small vessel lying directly above the external carotid

1The suprarenal bodies are situated further caudad on the kidney than in
Ophtodon.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 79

artery, but upon emerging from this foramen rapidly increases
in caliber. Then continuing caudad it passes over the efferent
branchial arteries, and when the head kidney is reached follows
along its ventral surface and terminates by anastomosing with
the corresponding cardinal vein to form the great precaval
trunk. Throughout its short course it receives numerous
branches from the dorsal branchial muscles and the head kidney,
which will be described in detail after considering the 3 princi-
pal trunks which go to make up the jugular vein.

(a2) External Jugular Veins (Pls. I and II, figs. 1, 5 and 15;
Ex.J.V.).— Of the 3 vessels which unite to form the jugular
vein this is the largest. It also arises from 3 rather large
trunks, the largest of which is the faczalis-mandibularis vein
(Pls) and) Ut} fios. 35 and) 22);'H.Man.V.).| This vessel’ has
its source in the anterior part of the lower jaw from the genzo-
hyowdeus vein (Pls. I and II, figs. 1 and 12; Ghs.V.), which
runs along the ventral surface of that muscle just outside of the
corresponding artery, which is a branch of the left hyoidean
artery. The facialis-mandibularis vein at first passes along
the inner side of the dentary bone, receiving numerous branches
from the mandibular portion of the adductor mandibule muscle.
Shortly before leaving the articular bone it receives a large
secondary mandibular vein, coming from the ventral side of
the muscle, and a posterior branch coming from the inner side
of the quadrate bone. The facialis-mandibularis vein then
makes a dorsal bend; leaving the corresponding artery it fol-
lows up behind the ramus mandibularis V, or ramus maxillaris
inferior of other authors, between the superficial and profundus
portions of the adductor mandibule muscle, receiving several
rather large branches from each. At the level of the levator
arcus palatini muscle it receives, from the rear, the hyoidean
vein.

Hyoidean Veins (Pls. I and II, figs. 1 and 12; Hyo.V.)—
These vessels have their origin in the hyohyoideus superior
muscles. Each vein runs along in that muscle some little dis-
tance ventrad of the hyoidean artery, which follows along on
the surface of the arch. The vein receives a branch from the
region of each branchiostegal ray and when the end of the arch

80 ALLEN

is reached it curves cephalad, following along the interhyal,
but above the minor hyoidean artery and the ramus hyoideus.
When the preopercular is reached the course of this vein is
dorsad behind the ramus hyoideus and when a little past the
middle of the preopercular, it passes with the nerve to the outer
surface of the hyomandibular through a foramen between the
hyomandibular and the preopercular. Here it receives a ven-
tral branch from the posterior part of the adductor mandibule
muscle, which follows along the outer surface of the preoper-
cular. The main stem then leaves the hyoidean ramus and
continues obliquely cephalad a little ventrad of the levator
arcus palatini and between the superficial and profundus por-
tions o yadductor mandibule, to unite with the facialis-man-
dibularis vein. ‘The combined trunk proceeds dorsad for
a short distance between the ramus mandibularis V and the
facial artery to the floor of the orbit; where it receives the
facialis-maxillaris vein.

Fracialis-maxillaris Veins (Pls. I and III, figs. 1, 17, and 18;
F.Max.V.). — Each of these vessels has its origin from a dorsal
and a cephalic branch. The larger dorsal branch arises as an
anastomotic vein from the orbito-nasal vein (see fig. 18); pass-
ing beneath the nasal sac some little distance cephalad of the
corresponding artery it receives at the level of the ventral surface
of the nasal sac a rather large vein coming from the region of
the palatine arch; and then continuing ventrad a short distance
the main stem passes under the maxilla artery and unites with
the maxilla vein. The maxz/la vein (Pls. I and III, figs. 1 and
17; Max.V.) has its source in a superficial and a profundus
branch from the premaxilla, which unite in the region of the
vomer. In its caudal course it receives several branches from
the ‘anterior part of the adductor mandibule muscle. After
uniting with the dorsal branch from the region of the nasal sac
the facialis-maxillaris vein proper crosses over the small facialis-
maxillaris artery, and continuing caudad between the ramus
maxillaris V or ramus maxillaris superior and the facialis-
maxillaris artery in the adductor arcus palatini from which it
receives several branches, it unites with the combined trunk of
the mandibular and hyoidean veins in the posterior part of the
orbit to form the external jugular trunk.

BLOOD-VASCULAR SYSTEM OF THE LORICATI SI

The facialis-maxillaris vein is much larger than the corre-
sponding artery. It returns most of the venous blood from the
region of the maxilla; while it is the orbito-nasal artery, which
furnishes this region with most of its arterial supply.

The external jugular vein (Pls. I and II, figs. 1, 5 and 15;
Ex.J.V.) is in itself a rather short trunk. It follows along in
front of the truncus infra-orbitalis or truncus buccalis-maxillo
mandibularis and the external carotid artery in the posterior
part of the orbit; passing over the hyomandibular bone it unites
with the orbito-nasal and internal jugular veins in front of the
prootic process.

(6) Internal Jugular Veins (Pls. I and II, figs. 1, 13 and 15;
In.J.V.). — What has been designated as the internal jugulars
return the venous blood from the eye, recti muscles, and the
brain. Each of these trunks might be said to have its source
from the rectus, ophthalmic, and iris veins (see fig. 15) and at
this point of union it also receives or sends off a large sinus-like
vessel,’ which extends caudo-mesad in the eye-muscle canal and
anastomoses in the median line with a corresponding sinus-like
vessel from the opposite internal jugular vein. This horse-shoe
shaped sinus incloses the encephalic artery and receives a pos-
terior branch from each of the external recti muscles. The
main internal jugular vein becomes greatly reduced in caliber
in passing through what might be called the internal jugular
foramen (a foramen between the alisphenoid, prootic, and para-
sphenoid process, through which pass the internal jugular, the
iris artery, and the ciliary nerve). Emerging from this foramen
the internal jugular receives the encephalic vein, coming through
the cranium through the small encephalic vein foramen (the
most cephalic of the 3 foramina in the prootic, through which
the encephalic vein and ciliary nerve pass). In front of the
prootic process the internal jugular unites with the external
jugular at an angle of about 75°. Coming in between these 2
trunks is the orbito-nasal vein, which might almost be said to
unite with the internal jugular before it joins the external |
jugular.

1'This connecting sinus may be the same as the cross vessel connecting the
two Bulbi ophthalmici described by Hyrtl (31, p. 236).

Proc. Wash. Acad. Sci., June, 1905.

82 ALLEN

frectus Vein (P1. Il, figs. 13 and 15; Rec.V.).— This ves-
sel arises from a ventral branch coming from the inferior rectus
muscle and acephalic branch coming from the superior and
internal recti muscles. Its course is then dorsad between the
optic nerve and the superior rectus muscle, and it unites with the
ophthalmic and iris veins to form the internal jugular trunk.
The vein from the external rectus muscle empties into the iris
vein and will be described more fully in connection with that
vessel.

Ophthalmic Veins (Pls. I and II, figs. 1, 5, 13, 15 and 19;
Oph.V.). — Each of these veins carries off the venous blood,
which has become collected in the chorozd senus. This sinus
(Pl. III, fig. 19; Chor.S.) is horse-shoe shaped, the anterior arm
being much longer than the posterior one. It lies between the
silver layer of the choroid and the similar shaped choroid ar-
tery, and occupying a large part of the space between the optic
nerve and the choroid gland, drains the entire choroid coat and
also the ventral portion of the iris. The venous blood from the
dorsal part of the iris is returned by the iris vein proper, which
will be described later on. The capillaries in the choroid may
reach the choroid sinus in either of 2 ways. They may become
collected into the chorozd vezns (PI. III, fig. 21 ; Chor. V.), which
break up into a fine rete mirabile of venous capillaries which
run parallel with the arterial rete mirabile capillaries, and
these in turn become collected entad into larger venous vessels
that empty into the choroid sinus; or they may reach the cho-
roid sinus directly by what I have designated as the dorsal
choroid vein or the 2 ventral choroid veins (Pl. III, fig. 19;
D.Chor.V. and V.Chor.V.), which empty into the anterior and
posterior horns respectively. The vein returning the venous
blood from the ventral portion of the iris is designated as the
ventral or minor tris vei (Pl. Ill, fig. 19; Ir.V.,)). This
vessel passes obliquely dorsad in the vascular layer of the
choroid, directly cephalad of the ramus ciliaris brevis, and
empties into the inner side of the anterior horn of the choroid
sinus. No similar artery was observed and it is probable that
the arterial supply for the ventral part of the iris comes from
the ventral choroid arteries rather than from the iris artery.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 83

The ophthalmic vern proper (Pls. I, II and III, figs. 1, 5, 13,
15 and 19; Oph.V.) arises as a sinus-like vessel from the dor-
sal region of the anterior horn of the choroid sinus, but grad-
ually tapers down into its caudal course, and when immediately
ventrad of the optic nerve receives a much smaller branch from
the posterior horn. Curving around to the posterior side of the
optic nerve it penetrates the silver layer of the choroid and the
sclerotic coat. Once outside of the eyeball the ophthalmic vein
pursues an oblique dorsal course, and, passing between the su-
perior and external recti muscles it unites with the rectus and iris
veins to form the internal jugular.

Iris or Ophthalmic Minor Veins (Pl. II and III, figs. 13,
15 and 19; Ir.V.).—A single iris vein arises from the capillar-
ies in the dorsal part of the iris. Together with the ramus cil-
iaris longus and the iris artery it passes ventrad a short distance,
between the silvery and vascular layers of the choroid (see fig.
1g), and then penetrates the silvery layer and the sclerotic coat.
After running along the posterior dorsal surface of the eyeball
it passes between the superior and external recti muscles, but
laterad to the ophthalmic vein. In its caudal course it receives
a branch from the external rectus muscle, and finally terminates
by uniting with the rectus and ophthalmic veins to form the
internal jugular.

Optic or Feetina Vein (Pl. Ill, figs. 19 and 20; Opt.V.). —
In the specimen from which figs. 19 and 20 were drawn I
noticed a small vein penetrating the sclerotic coat just ventrad
of the optic artery. Its connection with the larger vessels had
been destroyed before the vein was noticed, and internally the
vein was not injected. Several specimens were injected espe-
cially to demonstrate this vessel, but in every case this vein
failed to become injected. It is probable, however, that this
vein follows the course of the optic artery, returning the venous
blood from the lens, falciform process, and the retina, and very
likely empties into the ophthalmic vein.

As has already been stated in the first paragraph under (4)
the internal jugulars are connected with one another by a sinus-
like vessel, which crosses the eye-muscle canal. Leaving the
eye-muscle canal with the ciliary nerve and the iris artery,

84 ALLEN

through what was designated as the internal jugular foramen,
the internal jugular receives the encephalic vein shortly before
uniting with the external jugular and orbito-nasal veins to form
the jugular trunk.

Encephalic Veins (P\s. I, II, and III, figs. 1, 15, 23, 24, and
25; Enc.V.).—Each of these veins has its origin from 2
branches, an anterior and a posterior cerebral vein. The for-
mer returns the venous blood from the cerebrum, anterior sur-
face of the optic lobes, optic and olfactory nerves; while the
latter comes from the cerebellum, optic lobe, hypoaria, infundi-
bulum, and the auditory region.

Anterior Cerebral. Vem (P1. III, figs. 23 to 25 ;, A.Cer.V.).
— Cephalad, this vein arises from a small vessel running caudad
along the ventro-lateral surface of the olfactory nerve, and re-
ceives a branch from the olfactory lobe and one from the optic
nerve. About midway between the olfactory and the optic
lobes it unites with a much larger vein from the cerebrum. This
vessel arises from the inner parts of the cerebrum, and, passing
laterad between the cerebrum and the optic nerve, considerably
caudad of the corresponding artery, it unites with the small
cephalic vein just described. The combined vessel continues
caudad a short distance and when opposite the optic lobes re-
ceives 2 or more branches coming from the anterior part of the
hypoaria, infundibulum, hypophysis, and the anterior surface
of the optic lobes. Then curving obliquely cephalad, the ante-
rior cerebral vein proper crosses the III and IV nerves and the
posterior cerebral artery to unite with the posterior cerebral
vein in forming the encephalic trunk.

Posterior Cerebral ‘Ven (PISIll, figs. 23\to125 ;) P.Cer Ve):
— This vein has its source from 3 principal branches, namely:
the mesencephalic, cerebellum and auditory veins, the 2 latter
vessels uniting between the hypoaria and the optic lobes, im-
mediately before the mesencephalic vessel is received. The
auditory vein (P\. III, figs. 23, 23@ and 25; Aud.V.) arises
from branches coming from the utriculus, anterior and external
ampulla. The vein from the posterior ampulla empties into a
branch of the posterior encephalic vein, and will be described
under that vessel. Continuing cephalad for a short distance

BLOOD-VASCULAR SYSTEM OF THE LORICATI 85

the auditory vein anastomoses with the cerebellum vein (Pl. III,
figs. 23 and 25; Cer.V.), which arises in and leaves the cere-
bellum with the cerebellum artery, but below it. In its ventral
course it receives a superficial branch from the posterior surface
of the optic lobe, and, after uniting with the auditory vein, the
combined trunk continues cephalad a short distance between
the optic lobe and the hypoaria and ventrad of the posterior
cerebral artery before receiving the mesencephalic vein (See
fig. 23). The mesencephalic vein (Pl. III, figs. 23 to 25; Me.
V.) arises from the floor of the mesencephalon (optic lobe) and
penetrating ventrad through the crus, passes out between the
optic lobe and the hypoaria, in front of the III nerve and
mesencephalic artery, then crossing below the nerve and artery
it unites with the common vessel formed by the anastomoses of
the auditory and cerebellum veins to form the fosterzor cerebral
vein (figs. 23 to 25; P.Cer.V.). The course of this vein is
cephalad, directly below the posterior cerebral artery, between
the optic lobe and hypoaria, and between the trigemino-facial
complex and the IV nerve. Uniting with the anterior cerebral
vein midway between the cerebrum and the optic lobe it forms
the encephalic vein (Pls. I, II and III, figs. 1, 15, 23 and 25;
Enc.V.), which shortly leaves the IV nerve to follow trigemino-
facial complex, and when the facialis portion of the ramus
lateralis accessorius is given off the cranzal cavity vetn is re-
ceived. This vein (Pl. III, fig. 24; C.C.V.) follows along the
anterior surface of this nerve and anastomoses caudad with a
branch of the posterior encephalic vein, which follows along
the posterior surface of the vagus portion of the ramus lateralis
accessorius. Hence the venous blood from the adipose tissue
of the cranial cavity may reach the jugular vein through the
encephalic, or the posterior encephalic vein, or through both.
Then leaving the trigemino-facial complex, along the inner
surface of the ciliary nerve, the encephalic vein penetrates with
it through the most anterior foramen in the prootic, and here
empties into the internal jugular just before it unites with the
orbitonasal and external jugular in forming the main jugular
vein.

(c) Orbito-nasal Veins (Pls. I, II and III; figs. 1, 5, 13, 15,

86 ALLEN

17 and 18; O.N.V.).—Each of these veins has its origin
directly behind the maxilla, and, following caudad along the
ventral side of the corresponding artery, passes behind the
nasal sac, where it receives 2 veins coming from the nasal sac.
The smallest and most cephalic one is designated as the
anterior nasal sac vein (P|. III, figs. 17 and 18; N.S.V.,,). In
the specimen from which figs. 17 and 18 were drawn this
vessel arose from 6 anterior radial veins (see fig. 17). Each of
these radial veins runs along the outer or distal edges of the
secondary filaments of one of the primary filaments, and from
each of these secondary filaments there comes a branch, which
receives the capillaries from the inner connective tissue layer
of that secondary filament and from that portion of the primary
or radial filament. These radial filament veins unite with one
another at their bases and finally terminate in the anterior nasal
sac vein, which empties into the main orbito-nasal trunk. In
like manner the larger posterior nasal sac vein (P1. ILI, figs.
17 and 18; N.S.V.,,) arises from 8 posterior radial veins,
which take their origin from the secondary filament veins from
their respective radial or primary filament. The 2 nasal sac
veins are usually distinctly separated as shown in fig. 17, but
in a few cases I have noticed that they were connected by a
longitudinal vein, thus forming a continuous lateral vein into
which all the radial veins were emptied, and from which the 2
nasal sac veins had their source. Between these 2 nasal sac
veins, the orbito-nasal vein anastomoses with a branch of the
facialis-maxillaris vein (see fig. 18). After leaving the nasal
sac, the orbito-nasal vein pursues a general caudal course,
parallel with, but dorsad of, the orbito-nasal artery and mesad
of the olfactory nerve, and enters the orbit through the olfactory
foramen in the prefrontal. Once inside the orbit it leaves the
olfactory nerve and the orbito-nasal artery to pursue, with the
truncus supra-orbitalis or ramus ophthalmicus superficialis and
profundus, a sort of dorso-caudal course through the orbit.
Passing behind the superior oblique muscle it receives the
inferior oblique vein (Pl. Il, fig. 13; Inf.O.V.), coming up
from the outside of that muscle, and the swperzor oblique vein
(fig. 13: Sup. O.V.), coming down from the inside of that

BLOOD-VASCULAR SYSTEM OF THE LORICATI 87

muscle. Then continuing caudad, behind the superior rectus
muscle and mesad of the truncus supra-orbitalis, it arrives in the
posterior dorsal corner of the orbit, where it receives the sc/e-
rottc vern (Pl. Il, fig. 15; Scl.V.). This vessel, which arises
from the adipose tissue in the region of the anterior part of the
eyeball, runs obliquely caudad across it, mesad of the corre-
sponding nerve and artery. After receiving this branch, the
main orbito-nasal vein crosses above the ophthalmic and iris
vessels, and following around the eyeball for a short distance,
finally comes in between and unites with the external and
internal jugulars to form the great jugular vein.

The remarks made under the summary of the carotids apply
with equal force to the external and internal jugular veins.
These are simply arbitrary names given to the 2 largest veins
of the head region, which go to make up the common jugular
trunk.

2. Vessels Emptying Directly into the Jugular or into the
flead Kidney.

a. Veins Emptying into the Kidney. —'These veins include
the posterior encephalic and the first and second neural veins.
They do not empty at once into the jugulars, but penetrate the
dorsal surface of the head kidney, break up into smaller ves-
sels, which become reunited forming the renal veins, and these
empty into the jugular vein.

Posterior Encephalic Veins (Pls. II and III, figs. 16, 23 to
25; P.Enc.V.).— These veins may be said to concur in part
with the first neural or vertebral artery. Each of these veins
arises from a superficial capillary network from the dorsal sur-
face of the optic lobes; passing caudad over the cerebel-
lum it receives a superficial branch from it and several from
the adipose tissue surrounding the brain and the semi-circular
canals; and usually anastomoses with the cranial cavity vein
(see fig. 24), which empties into the encephalic vein. After
passing over the cerebellum the posterior encephalic vein
bends ventrad, following along behind the vagus portion of the
ramus lateralis accessorius to its origin from the dorsal root of
the vagus, and when the level of the oblongata is reached,

88 ALLEN

sends off, or receives, a cross vessel from the corresponding
vein on the opposite side. This cross vessel receives a branch,
coming caudad along the dorsal surface of the oblongata.
Whether it returns any of the venous blood from the cerebellum
I was unable to determine. In the neighborhood of the origin
of the vagus portion of the ramus lateralis accessorius from the
dorsal root of the vagus, the posterior encephalic vein re-
ceives an anterior branch or odlongata vein (Pl. Ill, fig. 24;
Obl1.V.), which has its source from the side of the oblongata
directly behind the roots of trigemino-facial complex, and
shortly receives a branch from the posterior ampulla, then run-
ning along the side of the oblongata, passes beneath the IX and
X nerves and finally terminates by emptying into the posterior
encephalic vein. Following along the dorsal root of the vagus
nerve the posterior encephalic vein leaves the brain case
through the vagus foramen in the exoccipital, but before leav-
ing the skull the large myelonal vein is received from the rear.
This vessel (Pl. III, figs. 23 to 25; My.V.) arises on the dorsal
surface of the myel as far back as the 9th pair of spinal nerves.
After running along on the dorsal surface of the myel fora
short distance it separates into a right and a left myelonal vein.
Each of these vessels runs along the lateral surface of the myel,
passing between the dorsal and ventral roots of the spinal
nerves, finally terminating by emptying into the posterior en-
cephalic vein. Along its cephalic course the myelonal vein
receives numerous vessels from the myel, and sends across
dorsal connecting branches, which unite with the correspond-
ing vein on the opposite side. Although the myelonal vein
empties into the posterior encephalic vein, still, not all of its
blood reaches the jugular through that vessel, but some of it is
carried off by the first 3 sfzzal vezns (Pls. II and III, figs.
16 and 24; Sp.V.). These vessels pass out with each alter-
nate pair of spinal nerves, and emptying into the neural veins,
which in the case of these anterior veins penetrate the dorsal sur-
face of the head kidney, and here break up into very small
veins, which again become collected into vessels that empty
into the jugular vein. The posterior encephalic vein is simply
a modified spinal vein, which after leaving the skull through

BLOOD-VASCULAR SYSTEM OF THE LORICATI 89

the vagus foramen, follows along behind the nerve and receiv-
ing the much smaller neural vein, penetrates the anterior dorsal
corner of the head kidney (see fig. 16). Within the head kid-
ney the posterior encephalic or the most anterior neural vein
breaks up into very small veins, which again become collected
and empty into the jugular vein.

(6) Veens Emptying Directly into the Jugulars. — Under this
head belong the opercular and the 3 dorsal branchial muscle
veins. The latter in addition to draining the branchial muscles
receive also the dorsal nutrient branchial veins from the bran-
chial arches. In OfAzodon these veins are always present,
but vary considerably in their distribution. Perhaps the most
common arrangement is shown in fig. 1.

Opercular Verns (fig. 1; Op. V.).— These veins arise on
the inner side of the operculars; running dorsad behind the
corresponding arteries, they curve ventrad, after leaving the
dorsal edge of the operculars, and after receiving a branch from
the levator operculi muscles of Vetter, empty into the jugulars
a little behind the first dorsal branchial muscle veins.

Dorsal Branchial Muscle Verns (fig. 1; Br.M.V, only the
second vein being lettered). — In the specimen from which fig.
I was drawn, the first of these vessels had its source in, and
received its principal supply from, the first dorsal nutrient
branchial vein (fig. 1; D.N.Br.V.). This vessel arises a little
below the dorsal bend, and is at first the most anterior of the 3
vessels in the dorsal part of the first branchial arch. In the
arch it receives a nutrient filament vein (fig. 2; N.Fil.V.),
coming from the inner margin of each filament. When the
dorsal bend of the arch is reached, the first dorsal nutrient
branchial vein crosses over and continues dorsad behind the
first efferent branchial artery. Then following along the outer
surface of the first obliquus dorsalis muscle from which it receives
a branch, it penetrates with the LX nerve through the first levator
arc. branch. internus muscle, and again crossing over the first
efferent branchial artery shortly after the carotid is given off,
finally empties into the ventral side of the jugular a little
cephalad of the opercular vein. The second dorsal branchial
muscle vein, in this specimen, takes its source from the union

go ALLEN

of the second and third dorsal nutrient branchial veins. The
combined vessel thus formed passes dorsad behind the second
levator arc. branch. internus muscle, and after receiving a
branch from it and another from the second obliquus dorsalis
muscle, terminates in the jugular. In this specimen the third
and last dorsal branchial muscle vein arose from 2 branches.
The most cephalic one is a dorsal nutrient branchial vein from
the last branchial arch, and the other has its source from the
pharyngo-clavicularis externus, pharynx, and the occipito-
clavicularis muscle. The dorsal branchial vessel thus formed
passes in a dorso-cephalic direction above the corresponding
artery. After crossing the last efferent branchial artery it
receives a good-sized branch coming from the last 2 internal
branchial levator muscles, and then empties into the jugular
directly behind the second dorsal branchial vein, but before
emptying into the jugular it receives the 7hymus ven from the
rear. This vein (fig. 1; not lettered) runs cephalad along the
ventral margin of the gland, receives several branches from it,
and shortly before reaching the anterior end of the thymus,
curves ventrad; crossing over the posterior encephalic and
jugular veins, finally terminates in the third dorsal branchial
muscle vein shortly before the latter empties into the jugular.
In another specimen from the one figured, the dorsal nutrient
vein from the second branchial arch joined the first dorsal bran-
chial muscle vein immediately after it had pierced the first
levator arc. branch. internus muscle. The second dorsal
branchial muscle vein took its origin from the third dorsal
nutrient branchial vein and received branches from the third
obliquus dorsalis muscle and the second levator arc. branch.
internus muscle; while the third and last dorsal branchial
muscle vein had its source from the fourth nutrient branchial
vein and a branch coming from the fourth obliquus dorsalis
muscle. The thymus vein emptied into the posterior encephalic
vein, and the vein from the pharyngo-clavicularis externus,
pharynx, and the occipito-clavicularis muscle, which is usually
the source of the last dorsal branchial muscle vein, crossed the
jugular and posterior encephalic veins and terminated in the
thymus vein.

BLOOD-VASCULAR SYSTEM OF THE LORICATI gi

3. Infertor Jugular Veins.

These vessels return the venous blood from the ventral mus-
culature of the head, heart, and ventral portion of the branchial
arches and correspond in the main to the pharynx artery. The
inferior jugular vein, however, does not become a paired vessel
until near its termination in the precaval vein.

The inferior jugular vein may be said to arise from a small
vein coming from the ventral surface of the tongue, the Zngual
ven (Pi We tier; lin. V.). This'vein continuing’ caudad
as the inferior jugular vein, passes in a median line above and
between the hyohyoideus superior muscles, after which it re-
ceives 3 pairs of veins, the first pair coming from the outer
posterior surface of the geniohyoideus muscles, the second from
the inner surface of the hyohyoideus superior muscles (Pl. I,
fig. 12; Hys.V.), and the third pair are the ventral nutrient
branchial veins from the first branchial arch. The latter ves-
sels (Pl. Il, fig. 12; N.Br.V.) drain the ventral half of the first
pair of arches. Each of them arises as a paired vessel in front
of the first efferent branchial artery. The nutrzent filament
veins (Pl. I, fig. 2; N.Fil.V.) from one side empty into one of
these branches and those from the opposite side into the other
branch.’ Further caudad these two branches unite forming a
single nutrient branchial vein into which a few of the most
ventral nutrient filament veins from both sides are poured. In
front of this nutrient branchial vein, running along the cephalic
margin of the arch, is another vein, which sends caudad cross-
vessels that empty into the main ventral nutrient branchial vein.
Continuing ventrad, cephalad of the efferent branchial trunk,
the first ventral nutrient branchial vein empties into the inferior
jugular vein. After collecting these veins the inferior jugular
passes caudad, above the thyroid gland and the ventral aorta;
receiving branches from the gland, other ventral nutrient branch-
ial veins, and several small veins coming from the obliqui ven-
trales muscles. Emerging from the last pair of afferent bran-
chial arteries the inferior jugular continues caudad, passing

1 Tt is of interest to note that the nutrient filament veins come-from the inner

margins of their filaments; while the nutrient filament} arteries are distributed
to the outer margins.

92 ALLEN

between the ventral aorta and the transversus ventralis muscle,
and when the posterior edge of this muscle is reached, which
is about midway between the last pair of afferent branchial
arteries and the ventricle, the inferior jugular bifurcates into a
very large 7zgh¢ and a much smaller /eft inferior jugular vein
(PiU, ie. 125 and Pal joys). abe, course ofeach ofthese
veins is then obliquely caudad, running along the ventral side
of the pharynx close to the pharyngo-clavicularis internus mus-
cle. They terminate by emptying into their respective pre-
caval veins. Throughout their course they receive branches
from the pharynx, the phayngo-clavicularis internus and ex-
ternus muscles, and shortly before dividing, the inferior jugular
received branches from the pharyngo-hyoideus and transversus
ventralis muscles, and the coronary vein.

The coronary vem (Pll, fig. 12; Cor.V.) arises froma
dorsal and a ventral branch, which run parallel with their
respective arteries. The dorsal vessel collects the venous blood
from the anterior part of the ventricle and the bulbus arteri-
osus; while the ventral branch drains only the bulbus. About
midway between the ventricle and the first pair of afferent
branchial arteries these 2 branches unite on the left side of the
ventral aorta in forming the main coronary vein, which finally
empties into the inferior jugular shortly after it emerges from
the last pair of afferent branchial arteries.

Beside this coronary vein, which drains the ventral aorta,
bulbus, and anterior part of the ventricle there is another sys-
tem of coronary veins, which terminate by emptying directly
into the auricle. The outer layer of the ventricle is a mass of
capillaries, which become collected on the ventral side into 4
or 5 veins that pass around to the dorsal side where some of
them anastomose, forming 2 or 3 vessels, which penetrate the
auricle close to the auriculo-ventricular valve. In one speci-
men several small veins were noticed to arise on, and penetrate
the dorsal surface of the auricle.

In Sebastodes melanops, beside the large right and the smaller
left inferior jugular veins, 2 other veins, laterad to these, were
observed. They arose from the pharyngo-clavicularis internus
and externus muscles, and passed caudad to empty into their
respective precaval veins.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 93

4. Ventral Veins.

These veins correspond to, and drain the region supplied by
the posterior part of the ventral artery: namely, the ventral or
pelvic fins, their muscles, and the ventral portion of the myotomes
forming the thoracic walls. Considerable variation is shown in
these veins, since they may arise as 2 rather large veins of equal
size or one small vein and one large one, but the most common
arrangement for Opfrodon is that shown in fig. 12.

The vessel designated as the rzght ventral vein (Pl. I, fig.
12; R.Ven.V.) is a deéper vessel than the ventral artery, and
terminates in the left hepatic sinus. This vein may be said to
have its source from 2 branches, a 77g? and a left ventral jin
dem (El. 11, ig. 12; R. and U-Ven.F:V.), which have their
origin in the right or left ventral fin ray canal. In these canals
the veins run behind the arteries, and receive a branch from
the center of each ray. Leaving the canal of the last rays each
of these veins crosses above the corresponding ventral ray
artery, and passes cephalad, for some little distance, between
the ventral or pelvic superficial adductor muscle and the ventral.
myotomes. Then after uniting with its fellow, the combined
trunk continues cephalad as the right ventral vein or the main
ventral vein. Along its course this vein and its 2 branches re-
ceive numerous vessels. Soon after leaving the ventral fin
canal, the left ventral fin vein receives a posterior ventral vein,
which runs parallel with the corresponding artery. This branch
receives several ventral intercostal veins (P\. Il, fig. 12; V.-
Intc.V.) from either side. In addition to receiving a ventral
intercostal vein from the septum between each alternate pair of
myotomes, each ventral fin vein receives several branches from
the superficial and profundus adductor muscles, and at least 2
branches, coming up between the pelvic bones from the super-
ficial and profundus abductor muscles. The right ventral vein
itself also receives at least 2 ventral intercostal veins from the
right side. In the specimen from which fig. 12 was drawn the
left ventral vein (L.Ven.V.) was a very short vessel, arising
from several ventral intercostal veins from the left side, but in
other specimens the left ventral vein was as large as the right,
and the vessel designated as the /eft ventral fin vein (fig. 12;

94 ALLEN

L.Ven.F.V.) instead of uniting with the right ventral fin vein
to form the right ventral vein, forms the principal venous sup-
ply for the left ventral vein.

In Hexagrammos and Scorpenichtys the ventral veins are
essentially the same as the last case described under Ophzodon ;
namely, the 2 ventral veins are of equal size, receiving their
venous supply from the right and left sides respectively. In
Scorpenichthys, however, the right and left ventral fin veins do
not leave the ventral fin ray canal with the artery from the last
ray, as is the case with Ophzodon and Hexagrammos, but may
leave the canal between any 2 rays, usually, between different
rays in the 2 different fins. In Sebastodes these 2 veins are of
equal size, but another condition is introduced. The 2 ventral
fin veins leave the ventral fin canal with their respective
arteries, anastomose, and the common trunk thus formed passes
cephalad parallel with the ventral artery, between the two pelvic
bones, and usually empties into the left ventral vein.

5. Subclavian Veins.

In Ophiodon there are 3 subclavian veins, returning the
venous blood from the region of the pectoral arch. Two of
these, coming from the outer or abductor muscles, unite in
forming the subclavian sinus which empties into the sinus veno-
sus in front of the precava, while the third one coming from
the rays and the inner or adductor muscles, pierces the anterior
fork of the kidney. This vessel does not empty directly into
the cardinal trunk, but first breaks up into smaller vessels,
which reach the cardinal through the renal veins.

Internal Subclavian or Subclavian Veins,,, (Pl. Il, fig. 14;
Sub.V..,,).—The vessel thus designated, in the main, cor-
responds with the internal subclavian artery. It receives its
supply in part from the pectoral rays, and in part from the ad-
ductor muscles, situated on the inner side of the pectoral arch.
This vessel has its origin from a dorsal and a ventral pectoral
fin vein, which unite in the pectoral ray canal, thus forming a
continuous vessel, which runs along behind the corresponding
pectoral fin artery. Within this canal it receives a small vein
returning the venous blood from each ray. In no 2 specimens

BLOOD-VASCULAR SYSTEM OF THE LORICATI 95

did these 2 veins leave the pectoral fin canal in the same places ;
in fact, they were not the same in the 2 different fins of
the same fish. In the fin from which fig. 14 was drawn the
dorsal branch left between the seventh and eighth rays, count-
ing dorso-ventrad, and the ventral branch left in the neighbor-
hood of the fourteenth ray. Each of these branches proceeded
dorsad, for some little distance, along the inner surface of the
superficial pectoral adductor muscle, and each branch received
numerous smaller branches from the superficial and profundus
adductor muscles. Uniting on the level with the scapula fora-
men they form the internal subclavian trunk, which continues
dorsad behind the subclavian artery. Shortly before the kidney
is reached it curves caudad, and passing between the first few
spinal nerves and the superficial adductor muscle, pierces the
ventral surface of the corresponding fork of the kidney. Once
within the kidney the internal subclavian rapidly decreases in
caliber, by sending off branches that break up into capillaries,
which finally reach the cardinal through the renal veins.

The vein designated as the external subclavian or subclavian
veins, (Pl. Il, fig. 14; Sub.V.,,)) has its origin from the super-
ficial and profundus pectoral abductor muscles, on the outer
surface of the pectoral arch. Coming through the scapula
foramen, cephalad of the external subclavian artery, it re-
ceives a branch from the profundus adductor muscle, and then
runs for a short distance below and behind the precaval vein,
where it receives the vein designated as the subclavian vein.)
(Pil teste oub.V..4)) “his vein takes its' source from, 2
branches, one coming from the ventro-cephalic portion of the
profundus abductor muscle, and the other from the similar part
of the profundus adductor muscle. The former penetrates the
coracoid foramen, and unites with the latter in forming the main
subclavian vein,,), which passes dorsad along the inner surface
of the profundus adductor muscle. Leaving this muscle,
subclavian vein,,, unites with the external subclavian vein to
form the subclavian sinus (Pl. Il, fig. 12; Sub.S.), which
empties into the sinus venosus directly behind the precaval vein,
but before uniting with the external subclavian, it receives a
vessel formed from a branch from the clavicle and the stevno-
hyotdeus vein (Pl. Il, figs. 12 and 14; Ster.V.).

96 ALLEN

In Hexagrammos and Sebastodes the subclavians are essen-
tially the same as in Ophzodon, except that no vessel corre-
sponding to subclavian vein,,, was observed. In Scorpenzch-
thys there were at least 3 znternal subclavian veins (P|. IV, fig.
30; Sub.V..,,); all of which broke up in the anterior fork of
the kidney. The external subclavian vein in Scorpenichthys
(Pl. IV, fig. 30; Sub.V.,,)) instead of emptying into the sinus
venosus, breaks up in the anterior fork of the kidney, cephalad
of the internal subclavians.

6. Hepatic Portal System.

This system of veins returns most of the venous blood from
the stomach, spleen, ceca and intestine. Some of the blood,
however, from the posterior part of the stomach and intestine,
reaches the right cardinal through the posterior mesenteric vein.
This vein anastomoses with the portal system in at least two
places. In Ofhzodon there are 2 distinct portal veins, which
terminate in the right and left lobes of the liver. The right
portal returns the blood from the right side of the stomach,
spleen, and a portion of the intestine; while the left portal
drains the ceca, ventral portion of the stomach, and a portion
of the intestine. In Ophiodon these 2 systems remain quite
well separated; nevertheless, their branches anastomose in
several places in the region of the posterior end of the stomach,
but within the liver none of their branches unite. Each of the
portals breaks up into capillaries in its respective lobe, which
reunite in forming the right and left hepatic veins, and these
vessels unite in a sinus before emptying into the sinus venosus.

(a) Fight Portal Vein (Pl. I, figs. 1 and 2; R.Por.V.).—
In Ophiodon the right portal trunk is in itself a very short ves-
sel, having its source from 2 principal trunks, one of them being
the right gastric vein, coming from the stomach, and the other
branch a vein formed by the union of the splenic and intestinal
vein, The right gastric vein (fig. 1, R.Gas.V.) has its origin
in the posterior or cardiac portion of the stomach, where it
anastomoses with branch Z of the posterior mesenteric vein (fig.
1, P.Mes.V.) and the posterior gastric vein, which is a branch
of the left portal. The course of the right gastric vein is

BLOOD-VASCULAR SYSTEM OF THE LORICATI 97

cephalad, below the right gastric artery and the right gastric
ramus of the vagus. Throughout its course it receives numerous
branches from the muscular coats of the stomach. Leaving
the anterior part of the stomach it crosses above the corre-
sponding artery and nerve, and the cceliac artery, and when
about midway between the stomach and the caudal tip of the
right lobe of the liver, directly behind a gland-like body marked
G. it unites with zztestenal vein). This vein (PI. I, figs. 1 and
6; Int.V.,)) usually arises in the region of the rectum by anas-
tomosing with branch Y of the posterior mesenteric vein (see
fig. 1). In its cephalic course in the adipose tissue surrounding
the intestine, lying below the corresponding artery, it ordinarily
sends off from one to 3 branches, which empty into the right
ceca vein or its posterior gastric branch. In the specimen
from which fig. 1 was drawn 3 such vessels were given off.
The 2 posterior ones emptied into the right posterior gastric
vein and the anterior one into the right ceca vein. Through-
out its entire course intestinal vein,,, receives numerous branches
from the intestine and when the spleen is reached, which is in
the neighborhood of the anterior or duodenum portion of the
intestine, it receives a large vein from that organ. The splenic
vem (Pl. I, figs. 1 and 6; Spl.V.) arises in the center of the
spleen from a fan-like system of vessels, which unite in a com-
mon stem, that leaves the anterior part of the spleen with the
splenic artery and soon empties into intestinal vein). Im-
mediately after receiving the splenic vein, intestinal vein),
usually, sends off or receives a connecting vein (Pl. I, figs. 1
and 6; C’.V’.), which unites with the anterior intestinal or
duodenum vein, a branch of the left portal. In another speci-
men this vein was seen to arise from the splenic instead of the
intestinal vein. Intestinal vein,,, terminates by uniting with the
right gastric vein, in the neighborhood of the right lobe of the
liver, to form the main right portal trunk. As has already
been atated) this ivessel (BIN) figs.) a and; 11; R.PoraVs)iis
in itself a very short trunk, which penetrates the apex of the
right lobe of the liver, and exhausts itself in that gland by
breaking up into numerous zzterlobular veins (fig. 11, I. Lob.
V.), which finally terminate in numerous venous capillaries.

Proc. Wash. Acad. Sci., June, 1905.

98 ALLEN

Shortly before entering the liver, however, the right portal re-
ceives a vein from a gland-like body, marked G in fig. 1, and
the anterior gall-bladder vein. The latter vessel (fig. 11, A.
G.BI1.V.) arises from the anterior part of the bladder, and like
the corresponding artery, anastomoses with the posterior gall-
bladder vein.

In some cases, as was also noted with the corresponding
artery, intestinal vein,,, does not always have its origin in the
rectum and anastomose with the posterior mesenteric vein and
the vessels emptying into the right ceca vein; but sometimes
arises much further cephalad, and the part of the intestine
usually drained by this vessel was poured into the posterior
mesenteric vein and the veins emptying into the right ceca
vein.

(6) Left Portal Vein (Pl. I, figs. 1,6 and 11; L.Por.V.). —
This is somewhat the larger of the two portals. In Ophzodon
it has its source, principally, from the right and left pyloric
czeca veins and intestinal vein,,. Of the 2 pyloric ceca veins,
thev2en7 (Pint igs. x and 6; R.Ca.V.)is the larger.” “Beside
receiving 3 or 4 large branches coming from the ceca it receives
a right, and a left posterior gastric vein (Pl. I, figs. 1 and 6;
R, and L.P.Gas.V.). The right vessel comes from the right
and ventral side of the posterior or cardiac portion of the
stomach, where its branches anastomose with those of the right
gastric vein and branch Z of the posterior mesenteric vein. In
the specimen from which figures I and 6 were drawn the right
posterior gastric vein received 2 branches from intestinal vein ,,
and the right pyloric ceca vein received a third one. In those
specimens in which these vessels unite with both intestinal
vein, and the right pyloric ceca vein or its posterior gastric
branch it would be possible for the blood to flow in either direc-
tion, but it is probable that the least resistance is toward the
pyloric czeca vein. Shortly before the right pyloric ceca vein
unites with the left in front of the pylorus, it receives a small
vein from the pylorus. Usually the /e/t pyloric ceca vein (see
Pl. I, figs. 1 and 6), is much the smaller. It receives about 2
branches from the czca and one or 2 small ones from the
pylorus. Both of the pyloric ceca veins run outside of their

BLOOD-VASCULAR SYSTEM OF THE LORICATI 99

corresponding arteries and unite in forming the left portal trunk
directly in front of the point of bifurcation of the cceliac artery.
Near its origin from the union of the two pyloric ceca veins
the left portal, or occasionally it is the right pyloric cca vein,
receives zutestinal vein. This vein (Pl. I, figs. 1, 6 and 11;
Int.V.,,.)) usually has its source from the ventral side of the
intestine close to the rectum. Its course is cephalad in the
adipose tissue below the intestine. Before going very far, how-
ever, it crosses to the upper side of the intestine, changing
places with intestinal vein,,.. Then proceeding cephalad above
the artery until the duodenum is reached, it crosses over the
intestine, intestinal artery,,), intestinal vein,,,, the anterior part
of the duodenum, the cceliac artery, and empties into the left
portal close to its origin from the two pyloric ceca veins. Con-
tinuing cephalad for a short distance between the stomach and
liver and to the left of the coeliac artery, the left portal receives
the anterior intestinal or duodenum vein (Pl. I, figs. 1 and
11; A.Int.V.), which returns the blood from the anterior loop.
The course of this vessel is at first directly behind the corre-
sponding artery; then after passing under intestinal artery,,, and
intestinal vein ,,, it ordinarily gives off or receives the connecting
vein (figs. 1 and 6; C./V.’), a small vein which usually anas-
tomoses with intestinal vein,,, a branch of the right portal.
Then after passing over the anterior arm of the duodenum from
which it receives a branch, it crosses the ceeliac artery, and after
following along behind the hepatic artery for a short distance
terminates in the left portal. The left portal enters the dorsal
surface of the liver through 5 large radicals or terminal branches
designated by the letters a to e (figs. 6 and 11). These vessels
immediately penetrate the large left lobe of the liver and break
up into the zzterlobular veins (fig. 11; I.Lob.V.), which, in
turn, break up into venous capillaries. Usually several veins
from the ventral surface of the stomach, designated as ventral
gastric veins (fig. 6; V.Gas.V.), empty into some of these radi-
cals, and some of the ventral gastric veins often penetrate the
dorsal surface of the liver and break up into venous capillaries
without emptying directly into the portal system. The posterzor
gall-bladder vein (fig. 11; P.G.B1.V.), which arises on the

I0O ALLEN

posterior dorsal surface of the bladder and anastomoses with
the anterior gall-badder vein, empties into radical a of the left
portal. This radical may also receive a similar, but smaller
vein from the ventral surface of the bladder.

An interesting vessel in Ophzodon is the left gastric vein
(Pl. I, figs. r and 6; L.Gas.V.), since it is not connected with
the portal system but terminates directly in the precava. This
vein has its origin in 2 branches from the left side of the
stomach, on either side of the left gastric artery. The ventral
branch is usually the larger; arising from the extreme posterior
end of the stomach, its branches anastomose with those of
branch Z of the posterior mesenteric vein. When the anterior
portion of the stomach is reached the smaller left gastric branch
crosses over the left gastric artery and joins the main stem of
the left gastric, and the combined vessel passes forward above
the left gastric ramus of the vagus and empties into the precava.
Still another small gastric vein arises from the anterior dorsal
surface of the stomach and terminates in the precava, above
the main left gastric vein.

As in other vertebrates the intestinal, gastric, and caeca veins
arise from capillaries in the connective tissue layer of the crypts
and the larger branches run in the muscular layers. Within
the liver the terminal branches or radicals of the two portals
exhaust themselves in the zz¢terlobular veins (fig. 11, I.Lob.V.),
which break up into venous capillaries, that reunite in forming
the central or intralobular veins, from which the sublobular
veins (fig. 11, S.Lob.V.) have their origin. The latter vessels
are the radicals, which by uniting, form the 2 hepatic veins
(fig. 11, R. and L.Hep.V.); which come from the right and
left lobes respectively, and terminate in a hepatic senus that
enters the sinus venosus from the rear. In the liver the main
trunks of the hepatic system lie beneath those of the portal
system.

As in the arteries, most of the variation of the veins in this
group occurs in the viscera. Nevertheless, all of the species
examined had a distinct right and left portal, which break up
in the right and left lobes respectively. In Sedastodes both
portals terminate in a common portal. In Hexagrammos the

BLOOD-VASCULAR SYSTEM OF THE LORICATI IOI

right portal anastomoses with radical a of the left portal. In
Scorpenichthys this union sometimes occurs, but with Off7-
odon it has never been observed. However, both Ophzodon and
Scorpentchthys have a connecting vein that interlinks these 2
systems in the region of the spleen.

(c) Right Portal in Hexagrammos, Scorpenichthys and Se-
bastodes. —In Hexagrammos, as with Ophiodon, this vessel
(P1. IV, fig. 27; R.Por.V.) has its origin from an intestinal, and
a gastric vein. The 7¢ght gastric vem (Pl. IV, fig. 27; R.-
Gas.V.) is essentially the same as in Ofphzodon, except that
there is no posterior mesenteric vein for it to anastomose with
on the apex of the stomach, and it runs on the opposite side of
the artery from what it does in the other 3 genera. The vessel
designated as zntestznal vein, (Pl. IV, fig. 27; Int.V..,)) is the
principal intestinal vein. It arises in the region of the rectum,
but soon crosses over to follow along the posterior arm of the
ileum from which it receives several branches before receiving
the splentzc vein’ (fig. 27; Spl.V.), and another good-sized
branch which drains the region supplied by intestinal artery...
Passing cephalad, parallel with, but below the corresponding
artery it crosses over intestinal vein,., the anterior part of the
intestine, the coeliac artery, radical @ of the left portal, and
when the stomach is reached unites with the right gastric vein
to form the right portal (fig. 27, R.Por.V.), This vessel im-
mediately passes under intestinal artery,,,, between the cceliac
and right hepatic arteries, along the posterior surface of the
gall-bladder, but behind the right hepatic artery. Here it re-
ceives a few small branches from the bladder and terminates
in 2 or 3 small branches in the right lobe of the liver, and also
anastomoses with radical @ of the left portal.

In Scorpenichthys the right portal (P1. IV, fig. 29; R.Por.V.)
has its source entirely from the right gastric and the splenic
veins. All of the intestinal veins empty into the left portal.
The right gastric vein (fig. 29, R.Gas.V.) is practically the
same as in Opfzodon; arising in the cardiac end of the stomach,

1In Hexagrammos the spleen is located much further caudad than is the case

with any of the other genera studied. Its position is much nearer the vent than
the stomach.

102 ALLEN

it anastomoses with branch Z of the posterior mesenteric, and
the posterior gastric veins. The splenzc vezn (fig. 29, Spl. V.)
leaves the anterior surface of the spleen, which is located
directly above the pylorus, and passes forward to unite with
the right gastric vein in forming the right portal, but immediately
after leaving the spleen it receives the posterior gastric vein
(fig. 29, P.Gas.V.), which in Ophzodon emptied into the right
ceeca vein, a branch of the left portal. The right portal, itself,
is almost identical with the same vessel in Ophzodon ; it receives
a small vein from a gland-like body marked G, and shortly
before entering the right lobe of the liver receives the anterior
gall-bladder vein which does not anastomose with the posterior
gall-bladder vein as in Ophzodon. Usually the right portal
breaks up in the small right lobe of the liver without anasto-
mosing with terminal branch a of the left portal.

Beside the ordinary branches which go to make up the right
portal in Ophzodon, there is an additional one in Sedastodes,
namely, the anterior air-bladder or atr-bladder retia mirabilia
vem (Fl IV, fie. 33; A: BI-V.).° This vessel arises irom: the
retia mirabilia venous capillaries, which are continuous with,
and run parallel to, the corresponding arterial retia mirabilia
capillaries. These venous capillaries unite in forming larger
vessels that terminate in the main anterior air-bladder vein,
which pierces the ventral wall of the bladder and empties into
the raght gastric vein. The latter vessel, as in Hexagrammos,
has its origin.in the posterior end of the stomach without hav-
ing any posterior mesenteric vein with which to anastomose.
Shortly after receiving the anterior air-bladder vein the right
gastric receives the vessel designated as intestinal vein,). This
vessel (fig. 31, Int.V..,,) arises in the rectum and drains the
posterior portion of the intestine. In its cephalic course, par-
allel with the corresponding artery, it follows along the poste-
rior border of the spleen; in Sebastodes flavidus (fig. 33) it was
seen to unite with the splenic vein as in Ofhzodon, while in
Sebastodes auriculatus both vessels emptied separately into the
right gastric vein. Shortly before joining the right gastric, or
splenic vein as it is in S. flavédus, intestinal vein,,) usually re-

ceives a posterior gall-bladder vein (figs. 31 and 33, P.G.BI.V.
Pp s gs: 3 3

BLOOD-VASCULAR SYSTEM OF THE LORICATI I03

and an anterior intestinal vein. Soon after leaving the spleen,
in front of the corresponding artery, the sp/enzc vein (fig. 31,
Spl.V.) receives the posterior gastric vein (fig. 31, P.Gas.V.)
from therear. This vessel arises from the ventral surface of the
stomach immediately behind the pylorus, and receives a small
branch coming from the ventral surface of the posterior end of
the intestine. After receiving this branch the posterior gastric
vein passes between the spleen and the ceca and joins the splenic
vein. The splenic vein in Sebastodes auriculatus after crossing
intestinal vein,.), and intestinal artery,.) unites with the right gas-
tric component, directly below intestinal vein,,,, to form the main
right portal. Shortly before entering the liver the right portal
receives a small branch coming from a gland-like body marked
G (figs. 33 and 34), anastomoses with the common portal trunk
(which will be fully described under the head of the left portal),
and in its course in the right lobe of the liver receives the azte-
rior gall-bladder vein. This vessel (figs. 33 and 34, A.G.BI.V.)
is always present, and sometimes returns the entire blood from
the gall-bladder. Its course is to the right and above the
ductus choledochus.

(d) Left portal vein in Hexagrammos, Scorpenichthys, and
Sebastodes. —In Hexagrammos the two pyloric ceca veins are
essentially the same as in Ophiodon, except that neither of them
receives a posterior gastric vein from the cardiac end of the
stomach. Close to its origin from the two pyloric czca veins
the /eft portal (PI, 1V, figs, 27 and 28; L.Por.V.) receives a
branch from the anterior arm of the ileum, designated as intes-
tinal vein, (fig. 27, Int.V..)), but which perhaps corresponds
to an elongated anterior intestinal or duodenum vein. On the
dorsal surface of the liver the left portal breaks up into 3 radi-
cals (figs. 27 and 28, a, 6 and c). Radical a is prolonged to
anastomose with the right portal, and soon after leaving the
main stem receives a very large ventral gastric vein (fig. 28,
V.Gas.V.), which may to some extent take the place of the
absent left gastric vein.

In Scopenichthys the left portal (Pl. IV, figs. 29 and 30;
L.Por.V.) receives both of the intestinal veins. The pyloric
czeca veins are essentially the same as in Ophzodon, except that

104 ALLEN

the pyloric branch of the left one extends backward on the car-
diac portion of the stomach as a sort of posterior gastric vein, and
anastomoses with branches of the posterior mesenteric vein;
while the posterior gastric vein proper empties into the splenic
vein instead of the right ceca vein as in Ophiodon. Intestinal
vein, (fig. 29, Int.V.,)) arises from the posterior end of the
iliac loop; the most dorsal of its branches anastomoses with
branch Z of the posterior mesenteric vein, and it receives a
branch coming from the region of the rectum. In its cephalic
course, intestinal vein, passes between the two arms of the
ileum, and receives a branch from the posterior part of the in-
testine designated as znéestznal vein, (fig. 29, Int.V..)), and the
anterior intestinal or duodenum vein (fig. 29, A.Int.V.). The
combined intestinal trunk thus formed passes under the anterior
arm of the duodenum and joins the left portal close to its origin
from the 2 pyloric ceca veins, but before emptying into the
left portal it receives or sends off a connecting vern (fig. 29,
C’.V’.) that unites with the splenic vein. After reaching the
great left lobe of the liver the left portal immediately gives off
to each side numerous terminal branches or radicals, which
break up into the interlobular veins. As in Ophzodon, except
in a very few cases, radical a of left portal does not anastomose
with the right portal; it, however, receives the posterior gall-
bladder vein (fig. 30. P.G.BI.V.), and also a very large ventral
gastric vein (fig. 30, V.Gas.V.), which anastomoses anteriorly
with the left gastric vein and posteriorly with a branch of the
posterior mesenteric vein.

As in Ophiodon there is a left gastric vein (fig. 30, L.Gas.-
V.) emptying directly into the precava and two smaller left
gastric veins; one of which empties into the precava and the
other into the left fork of the kidney ; while the main left gastric
vein anastomoses with branches of the ventral gastric vein,
which has branches that anastomose with branches of the pos-
terior mesenteric vein.

The left portal in. Sebastodes (P1. IV, figs. 30 and 31; L.-
Por.V.) is a rather insignificant vessel, having its source from
a vessel designated as intestinal vein, and the right pyloric
cfeca vein. Intestinal vein, (fig. 31, Int.V....) returns the

BLOOD-VASCULAR SYSTEM OF THE LORICATI 105

blood from the ileum; passing beneath intestinal vessels,,,) and
the splenic vessels, it crosses under the anterior part of the
spleen, where it joins a common trunk formed by the union of
the right pyloric czca vein and a very large pylorus vern (fig.
32, Pyl.V.). The common trunk thus formed is the left portal,
but instead of breaking up into numerous radicals it empties
with the left pyloric ceca vein (fig. 32, L.Cae.V.) and the
ventral gastric vein (fig. 32, V.Gas.V.) into the common portal
vein (fig. 32, C.P.V.). By anastomosing with the common
portal, the right portal might also bé said to empty into the com-
mon portal.

Summary of the Portals. —As in the case with the corre-
sponding arteries, intestinal veins,, .,a,) are arbitrary names given
to the two principal intestinal veins. Considerable variation
occurs in these two veins in the same species, but in Ophzodon
the vessel designated as intestinal vein,,, arises in the posterior
part of the intestine, and in its cephalic course along the ventral
side of the intestine receives the splenic vein, and joining the
right gastric vein forms the right portal. The corresponding
vein in Ylexagrammos pursues a similar course ; while in Scope-
nichthys the two intestinal veins unite and empty into the left
portal; and in Sedastodes intestinal vein,,, drains only the pos-
terior part of the intestine, and may unite with the splenic vein,
or each of these vessels may empty separately into the right
gastric vein to form the right portal. In every case the right
portal breaks up in the right lobe of the liver. The vessel
designated as intestinal vein,,) in Ophzodon arises from the
ventral posterior end of the intestine and terminates in the left
portal. In Hexagrammos this vessel might possibly correspond
to an elongated duodenum artery; while in Scorpenzchthys if
this vessel is represented at all, it unites with intestinal vein,,)
and the combined trunk empties into the left portal; and in
Sebastodes this is the principal intestinal trunk, arising from the
iliac loop it unites with the right pyloric czeca vein to form the
left portal trunk. All the genera but HYexagrammos have a
posterior gastric vein; in Ophzodon it terminates in the right
pyloric ceca vein; while in Scorpenrchthys and Sebastodes it
empties into the splenic vein, a branch of the right portal.

106 ALLEN

Ophiodon and Scorpenichthys have a left gastric vein, which
empties into the precava; while in Sedastodes and Hexagram-
mos the ventral gastric veins are greatly enlarged, and evi-
dently to some extent take the place of this vessel, nevertheless
in Scorpenichthys the ventral gastric is a good sized vessel and
anastomoses with the right gastric vein. In Ofhiodon and
Scorpenichthys there is a grand anastomosis in the cardiac
portion of the stomach of the branches of the right gastric, left
gastric, ventral gastric, posterior gastric and posterior mesen-
teric veins. Usually the right and left pyloric caeca veins unite
to form the left portal, but in Sebastodes the right pyloric ceca
vein joins intestinal vein,,, to form the left portal, and the left
pyloric ceca vein empties into the common portal trunk. Ofphz-
odon and Scorpenichihys have a connecting vein in the region
of the spleen that links the 2 portal systems; in Ophzodon it
usually connects intestinal vein,,) with the anterior intestinal or
duodenum vein; while in Scorpenichthys it connects the splenic
and common intestinal veins. Within the liver the 2 portals are
usually distinctly separated in Ophzodon and in Scorpenichthys ;
while in Hexagrammos radical a of the left portal anastomoses
with the right portal; and in Sedastodes both portals together
with the ventral gastric and left pyloric czca veins unite in
forming a common portal trunk, which gives off numerous
radicals that break up into the interlobular veins.

47. Leenal Portal System.

Like the hepatic portal system the renal portal system con-
sists of two principal venous trunks, which are connected by a
system of venous capillaries within the kidney. One of these
trunks, the caudal vein, arises in the region of the tail and pur-
sues a cephalic course in the hemal canal, immediately below
the caudal artery, receiving the neural veins from above and
the hemal veins from below. Piercing the dorsal surface of the
kidney it bifurcates into a right and left renal portal vein; each
of these sends off numerous afferent renal veins that after
breaking up into capillaries reunite in numerous efferent renal
veins, which terminate in, and form, the right cardinal vein.
This trunk starts in the posterior end of the kidney, passing

BLOOD-VASCULAR SYSTEM OF THE LORICATI 107

cephalad through the center of this organ; it follows the right
fork of the kidney and unites with the right jugular to form the
right precava. Throughout its course it receives numerous
branches, which will be described in detail later on. There is
also a smaller left cardinal for the left lobe of the kidney,
which will also be considered under a separate head.

(a) Caudal’ Vern (P\. I, figs. 1, 7, 8, 9 and 10; Cau.V.):—
This trunk has its origin in the region of the last vertebra from
a right and left branch; both of which have a more superficial
course than the corresponding arteries. The right caudal
vein (fig. 7, R.Cau.V.) is much the shorter; it arises from
the region of the tail and passes cephalad between the super-
ficial and profundus muscles, and when the last vertebra is
reached, curves inward, and after receiving a dorsal branch
joins the larger /eft caudal vein. The latter vessel (figs. 1 and
7; L.Cau.V.) has its origin from a dorsal and a ventral branch
in the caudal fin ray canal. These branches lie immediately
behind the corresponding lymphatic and arterial vessels. They
receive a branch from the central canal of each ray, coming
from the fin membrane and the fin ray muscles. Uniting be-
tween the two hypural bones the dorsal and ventral branches
form the /eft caudal vern (figs. 1 and 7, L.Cau.V.), which
passes cephalad between the superficial and profundus caudal
fin muscles, receiving branches from each. In the region of
the last vertebra it receives a dorsal branch and curves inward
to unite with the right caudal vein, but before joining the left
caudal vein to form the main caudal vein, each of the caudal
veins appears to receive a vessel from the caudal lymphatic
sinus. The course of the caudal vein is cephalad in the hemal
canal, immediately below the caudal artery; and in its course
to the kidney receives a dorsal branch from in front of each
alternate neural spine, and a ventral branch from in front of
each alternate hemal spine.

Each neural vein (fig. 1; Neu.V.) has its origin from a
cephalic and a caudal branch; the latter returns the venous
blood from superficial and profundus levator and depressor
muscles of that ray; while the former returns the blood from
the corresponding muscles of the preceding ray, and each

108 ALLEN

branch receives a vessel coming from behind the ray. These
2 branches unite at about the level of the apex of the neural
spine, forming the neural vein proper. At this point the neural
vein receives the dorsal lateral vein (fig. 1; D.Lat.V.), return-
ing the blood from the dorsal region of the 2 neighboring myo-
tomes, and immediately after receiving this branch the neural
vein passes obliquely ventrad between the neural lymphatic
vessel and the neural spine. Then curving forward and out-
ward it crosses the neural canal, the centrum, the dorsal aorta,
and empties into the caudal vein. In crossing the vertebral
column it receives a sfenal vern, coming through the spinal
foramen from the myel, and the medzan Jateral vern (fig. 1;
M.Lat.V.), returning the blood from the central region of the 2
adjacent myotomes. The hema/ vezns pursue a similar course
from the ventral side of the body. Each of these vessels (fig.
1; Hez.V.) has its source from the superficial and profundus
levator and depressor muscles of 2 successive anal rays. In
the region of the apex of the hzmal spine it receives the ven-
tral lateral vein (fig. 1; V.Lat.V.), coming from the ventral
portion of the two adjacent myotomes. Then passing obliquely
dorsad between the hzemal lymphatic vessel and the hemal
spine it empties into the caudal vein. This is the normal
arrangement of a neural or a hemal vein; occasionally, how-
ever, a neural or a hemal vein may drain the region of 3 or
even 4 myotomes, and a neural vein may cross either side of
the vertebral column. Usually between the first and second
caudal vertebre the caudal vein receives the urinary bladder
vein (figs. r and 10; Ur.B.V.), coming from the posterior sur-
face of the bladder. Very often, however, as is shown in fig.
10, this vein does not empty into the caudal vein, but penetrates
the posterior ventral end of the kidney and reaches the cardinal
through the renal veins.

After passing through the hemal canal of the first caudal
vertebra the caudal vein curves ventrad and pierces the dorsal
surface of the kidney and becomes the renal portal vein.

Shortly after the caudal vein, or renal portal as it really is,
penetrates the kidney it receives a rather large trunk designated
as the posterior mesenteric vein (Pl. I, figs. 1 and 10; P.-

BLOOD-VASCULAR SYSTEM OF THE LORICATI 10g

Mes.V.). This vessel arises from 2 good sized branches
designated as Y and Z (see fig. 1). Branch Z which is strictly
a gastric vein, takes its origin from several branches coming
from the posterior or cardiac end of the stomach; one of which
anastomoses with the right gastric vein; and 2 other branches
anastomose with branches of the left gastric and posterior gas-
tric veins. Thecourse of branch Z is dorso-caudad ; passing to
the left of the intestine and its vessels, it unites with branch Y
directly below the reproductive organs. Branch Y, which is
distinctly an intestinal vein, drains the posterior end of the
intestine, and usually anastomoses with intestinal vein ,,); pass-
ing caudad it joins branch Z in forming the main posterior gas-
tric stem, which passes between the reproductive organs, with-
out receiving any branches, penetrates the posterior ventral
surface of the kidney, and passing to the left of the right
cardinal empties into the renal portal vein. It would be possible
for the blood in the posterior mesenteric to flow in either direc-
tion, but it is probable that the least resistance is toward the
kidney.

After receiving the posterior mesenteric vein the caudal or
renal portal vein bifurcates into a r7ght and a left renal portal
ven or vena renalis advehens (figs. 1 and 10; Ren.P.V.).
These trunks run cephalad for some little distance through the
dorso-lateral part of the kidney, and gradually decrease in
caliber by giving off numerous ventral branches, the aferent
renal veins or venae renales advehentes (figs. 1 and 10,
A.Ren.V.). These vessels break up into rather coarse venous
capillaries near the lateral surface of the kidney, and become
collected ventrad and mesad by the small efferent renal veins
or venae renales revehentes (figs. 1 and 10; E-Ren\. Vs). oe
cross section through an injected kidney hardened in formalin
shows us that these vessels, many of which are visible from the
ventral side of the kidney, empty into the right cardinal from
every direction.

(6) The right cardinal vein (Pl. I, figs. 1, 5 and 10;
R.Car.V.), which is the principal cardinal has its source
mainly from the efferent renal veins; it arises in the extreme
caudal end of the kidney, below the caudal vein, and passes

IIO ALLEN

cephalad through the center of the kidney until the kidney
forks, when it follows the right fork. In the region of the last
branchial arch it unites with the right jugular in forming the
right precava (Pls. I and II, figs. 5 and 12; Prec.V.) or the
ductus Cuvierté as it is often called, which encircles the right
side of the cesophagus and empties into the sinus venosus in
front of the subclavian sinus.

(c) Other Vessels Emptying into the Kidney. — Beside the
posterior mesenteric and caudal veins there are several other
vessels, which penetrate the kidney and reach the right cardinal
in one way or another.

First under this head might be mentioned the spermatic vezns.
In the female (fig. 1) numerous branches arise from the lateral
surfaces of the ovaries and unite in a longitudinal vessel, that
has its origin from the anterior surface of the urinary bladder
and the oviduct. From this longitudinal vessel at least two
spermatic veins (fig. 1; Sper. V.) have their origin; passing dor-
sad they terminate in one way or another in the kidney: they
may empty directly into the right cardinal, or the renal portal
vein, or they may reach the right cardinal through the efferent
renal veins. Inthe male (see fig. 10) there is no longitudinal
trunk, and the spermatic veins arise directly from numerous
branches coming from the inner surface of the testes. In this
specimen the most anterior spermatic vein emptied into an affer-
ent renal vein, the second one broke up into capillaries, and the
last 2 joined the posterior mesenteric vein within the kidney.
The zeurals as in the caudal region drain the region of 2 myo-
tomes, passing ventrad between the neural lymphatic vessel and
the neural spine, they penetrate the dorsal wall of the kidney, but
instead of emptying directly into the right cardinal, break up
into capillaries that reunite in the efferent renal veins. The
intercostal veins (fig. 1; Intc.V.) corresponding to the hemal
veins of the caudal region, arise from 2 myotomes of the thor-
acic walls; passing dorsad behind the intercostal lymphatic
vessel they penetrate the ventro-lateral edge of the kidney,
break up into capillaries, and reach the right cardinal through
the efferent renal veins. In the cephalic part of the thoracic
wall they anastomose ventrally with the ventral intercostal

BLOOD-VASCULAR SYSTEM OF THE LORICATI Teh

veins. Usually, there are 2 suprarenal verns (fig. 10, Sr.V.),
which pass inward and join the right cardinal.

(d) The left cardinal vein (figs. 1 and 5; L.Car.V.) is a very
short and unimportant vessel; having its source entirely from
the anterior end of the left fork of the kidney. The blood from
the posterior part of this fork reaches the heart through the
right cardinal. The left cardinal unites with the left jugular in
forming the left precava, which passes around the left side of
the cesophagus and terminates in the sinus venosus.

(e) feenal Portal System in Scorpenichthys, Hexagrammos
and Sebastodes. —In each of these genera the renal portal sys-
tem is in the main substantially the same. Some minor varia-
tions are noted in the 3 following paragraphs.

The renal portal system in Scorpenichihys is essentially the
same as in Ophzodon. The caudal vein after passing through
the hazmal canal of the first caudal vertebra penetrates the
dorsal surface of the kidney, and breaks up into two renal por-
tal veins. As in Ophiodon a posterior mesenteric vern (fig. 29,
P.Mes.V.) is also present, which arises from a gastric and an
intestinal branch, and after passing over the urinary bladder
from which it receives a branch, penetrates the posterior apex of
the kidney, terminating in the renal portal; but the distance
it has to go cephalad in the kidney is much greater than in
Ophiodon, and numerous branches are given off, which reach
the cardinal through the efferent renal veins; so that the pos-
terior mesentric vein is much reduced in caliber upon joining
the renal portal. It is of interest to note in this connection that
in Enophrys and Calycilepidotus, 2 genera of the family Cot-
tidze, no such vessel as the posterior mesenteric was noticed.
As regards the spermatic veins, they are also of especial in-
terest, coming in midway between Offzodon and the peculiar
arrangement found in Sedastodes. In the female there is a
right and a left spermatic vein (fig. 29, R. and L.Sper.V), each
of which receives numerous branches coming from the lateral
surfaces of their respective ovaries. From each of these longi-
tudinal veins there arise a cephalic and a caudal vessel; both
of which unite with corresponding vessels from the opposite side
to form the spermatic veins proper (fig. 29; Sper.V.,,,,,), and

II2 ALLEN

each of these veins empties directly into the right cardinal, which
in Scorpenichthys runs along the ventral surface of the kidney.
In both male and female the right and left spermatic veins are
continued some little distance cephalad of the reproductive
organs, and empty into their respective cardinal veins, a little
behind the point of union of the cardinals with the jugulars to
form the precava.

The caudal vein (fig. 27; Cau.V.) in Hexagrammos after
passing through the first caudal vertebra gives off an anterior
and a posterzor renal portal vein (fig. 27; Ren.P.V.) The
former is the principal renal portal vein; it continues cephalad
along the dorsal surface of the kidney, and breaks up into
numerous afferent renal veins. In one specimen this vein
appeared to empty directly into the right cardinal vein. The
smaller posterior renal portal breaks up in the caudal end of the
kidney. One of its branches receives the vein designated as
the wrenary bladder vein (fig. 27; U.B1.V), which may to some
extent be analogous to the posterior mesenteric vein of Ophzo-
don and Scorpenichthys; it has its source from a meshwork of
small veins on the rectum, which anastomose with branches of
intestinal vein,,); passing across and along the dorsal surface
of the bladder from which it receives several branches, it pierces
the ventro-caudal end of the kidney, and gives off several
branches in the kidney before uniting with a branch of the
renal portal. The rzght cardinal (fig. 27; R.Car.V.) as in the
other genera arises in the extreme posterior end of the kidney,
and passing cephalad close to the ventral wall, unites with the
right jugular in the right fork of the kidney to form the right
precava. The veins from the caudal region of the ovaries
empty into a longitudinal vessel that passes between the ovaries ;
farther forward this vein bifurcates, one branch running along
the dorsal surface of the left ovary and the other along the
right; both of them receiving numerous branches from the lat-
eral surfaces of their respective ovaries. From the right longi-
tudinal spermatic vein there arise an anterior and a posterior
branch, both of which unite with the corresponding branches
from the left longitudinal spermatic vein in forming the main
anterior and posterior spermatic veins (fig. 27, Sper.V.a) ana
()) Which empty directly into the right cardinal.

BLOOD-VASCULAR SYSTEM OF THE LORICATI | I13

All species of Sedastodes examined had a distinct renal por-
tal system, which in the main resembled Ophzodon; however,
the renal portal veins extend much further cephalad, there is
always one or more posterior air-bladder veins emptying into
the renal portal system, and there is no posterior mesenteric
vein. The kidney itself differs considerably in shape from that
of the other genera; while it usually occupies a large portion
of the dorsal part of the short thoracic cavity, still a large por-
tion of the organ is crowded cephalad into the two forks. The
caudal vein (Pl. 1V, fig. 31; Cau.V.) after piercing the pos-
terior dorsal side of the kidney continues cephalad along the
dorsal surface of the kidney for some little distance as a renal
portal vecn and not until the kidney forks does this vein sepa-
rate into the renal portal vems (fig. 31, Ren.P.V.). These
veins continue cephalad in their respective lobes until near the
point of union of the cardinals with the jugulars, giving off
numerous afferent renal veins, and the renal portal itself re-
ceives the following vessels. First, the spermatic vern (fig. 31 ;
Sper.V.), which is formed from the posterior union of the right
and left spermatic veins. In its dorsal course about midway
between the reproductive organs and the kidney it receives the
urinary bladder vein (fig. 31; Ur.Bl.V.), and immediately be-
fore emptying into the renal portal, a small swprarenal vern.
Shortly after receiving the spermatic, the caudal or renal por-
tal receives a rather large fostertor air-bladder vein (fig. 31;
P.A.BI.V.), which arises from a regular network of vessels on
the posterior end of the air-bladder. In the specimen from
which fig. 31 was drawn, two smaller posterior air-bladder
veins were also noticed; one of which terminated in the renal
portal vein, and the other in the right cardinal. Usually, how-
ever, there is but one posterior air-bladder vein, and it may
empty into either the right cardinal or the renal portal vein.
The right cardinal is almost identical to the similar vessel of
the other genera, and a description of it is unnecessary.

VIII. VASCULAR SYSTEM IN ANOPLOPOMA.

Three specimens of this species were brought in by Chinese
fishermen when this paper was about finished. All were in-
Proc. Wash. Acad. Sci., June, 1905.

114 ALLEN

jected, but only one satisfactorily, the other specimens having
been badly torn by the hooks. Upon dissection several interest-
ing variations were noticed, and it seemed desirable to include a
representative of the family Azoplopomatide in this paper.

Carotid Artertes.—In Anoplopoma there are no common
carotids ; both carotids arise separately from the dorso-cephalic
corner of the first efferent branchial artery. The znternal
carotid (fig. 35; 1.Car.A.), which is given off first, presents no
peculiarities. While the external carotid (fig. 35; E.Car.A.)
is a much smaller vessel than in the other genera, and simply
supplies the facial region without anastomosing with the hyoi-
dean artery to form the mandibular artery ; it immediately gives
off the vessel designated as the fseudobranchial or afferent
pseudobranchial artery (fig. 35; Ps.A.), which is as large as
the external carotid, and which might be said to arise with the
external carotid from the first efferent branchial artery. The
course of the pseudobranchial artery is ventrad behind the hyo-
mandibular, exhausting itself by giving off numerous afferent
pseudobranchial filament arteries. Near its distal end the
pseudobranchial artery receives the dorsal branch of the hyoi-
dean artery, and it is probable that the hyoidean artery furn-
ishes the pseudobranch, especially the ventral part of it, with
some of its blood supply, but most of it evidently comes from
the pseudobranchial artery, which is much larger at its source
from the external carotid than at the point of anastomosis with
the hyoidean artery. This arrangement somewhat resembles
the pseudobranchial supply in Gadus, according to Miiller (50)
and Parker (61), but differs from it considerably. In Gadus the
afferent pseudobranchial artery is a branch of the hyoidean
artery, and the dorsal continuation of the main stem, which is
much reduced in caliber, anastomoses with the internal carotid
of the circulus cephalicus. |

FTyoidean Arteries (fig. 35 ; Hyo.A.).— One of the most strik-
ing differences in the circulatory system of Azoflopoma is in
connection with this vessel. As in Ophzodon each hyoidean
artery has its origin from the ventral ends of the first efferent
branchial artery. Passing along the dorsal surface of the hyoid
arch it gives off the characteristic branch to the branchiostegal

BLOOD-VASCULAR SYSTEM OF THE LORICATI EES

rays and then follows along in front of the interhyal, but when
the preopercle is reached, instead of passing through a foramen
formed by the symplectic, hyomandibular, and preopercular
and anastomosing with the facialis-mandibularis artery to form
the mandibular artery as in Ophzodon, it bifurcates ; the ventral
branch passes through the above mentioned foramen to become
the mandibular artery (fig. 35, Man.A.); while the dorsal
branch passes along the inner surface of the preopercle, gives
off a rather large opercular artery, and terminates in the
pseudobranchial artery.

Jugular Veins (fig. 35, J.V.).— The jugulars and their
branches are practically the same as in Ophzodon.

The first pair of epzbranchzal arteries (figs. 35 and 36; Epbr.
A.) unite in forming the dorsal aorta, and the second pair,
the cceliaco-mesentric; there is an opening into the aorta from
the coeliaco-mesenteric artery, corresponding to the common
chamber of Ophzodon, but the subclavians arise separately from
the dorsal aorta, opposite the opening into the cceliaco-mesen-
TenG:

Subclavian artertes.— Each subclavian (fig. 36, Sub.A.)
after leaving the head kidney passes to the inner musculature
of the corresponding pectoral fin. Here it separates into the
subclavian artery proper, which is essentially the same as in
Ophiodon, and a hypobranchial artery. This vessel (fig. 36;
Hypobr.A.) passes ventrad a short distance, gives off a large
branch, designated as the posterior ventral artery (fig. 363
Ven.A.,,)) which passes ventro-caudad, supplying the ventral fin
musculature and terminates in the right and left ventral fin
arteries. The main stem of the hypobranchial passes cephalad
and ventrad, and together with the corresponding vessel from
the opposite side anastomoses with the anterior ventral artery.
On the left side the hypobranchial artery has no posterior ventral
branch. The hypobranchial artery in Anxoflofoma may not be
homologous with the similar named vessel in Ophiodon, which
is really a branch of the ventral artery and anastomoses with a
branch of the subclavian.

Only one subclavian venous trunk (fig. 36; Sub.V...)) was
noticed. It arose from an external and an internal branch.

116 ALLEN

The outer subclavian vein penetrated the scapula with the cor-
responding artery and joined the internal subclavian vein in
forming the common subclavian trunk, which terminates in its
respective horn of the kidney.

The vessel designated as the anterdor ventral artery (fig. 36;
Ven.A.) arises from the ventral union of the second right and
left efferent branchial arteries; principally, however, from the
second left efferent branchial artery. After passing over the
combined trunk of the third and fourth afferent branchial ves-
sels it gives off the pharynx artery. This vessel (fig. 36;
Phar.A.) supplies the pharynx region, and soon sends off the
coronary artery (fig. 36; Cor.A), which passes along the dorsal
side of the ventral aorta to the heart. In all other genera studied
the pharynx artery arose directly from the second or the third
efferent branchial arteries. The anterior ventral artery evi-
dently corresponds to the ventral artery of the other species ;
except that it extends only to the origin of the pelvic arch. In
addition to giving off the pharynx artery it sends off branches
to the sterno-hyoideus muscle and anastomoses with the 2 hypo-
branchial arteries. It would be possible, however, in Azoplo-
poma for blood in the anterior ventral artery to reach the ventral
fins by passing through the right hypobranchial artery into the
posterior ventral artery. By the separation of the right hypo-
branchial from the subclavian we would have in the anterior
ventral, right hypobranchial, and posterior ventral arteries an
irregular shaped vessel corresponding somewhat to the ventral
artery of the other genera.

As in Sebastodes, there is in addition to the main inferior jugu-
lar and left branch, a right inferior jugular, which drains the
ventral branchial muscles from the right side and empties into
the right precava.

Caliaco-mesenteric Artery. — This trunk (fig. 37; Coe.Mes.-
A.) upon reaching the cesophagus separates into the cceliac and
mesenteric arteries respectively. The mesenterzc artery soon
divides into intestinal artery,,, and a short stem from which the
right and left gastric arterzes have their source. The latter
vessel (figs. 37 and 38; L.Gas.A.) makes a cephalic curve
across the cesophagus and continues on the left side of the

BLOOD-VASCULAR SYSTEM OF THE LORICATI IRAE

stomach to the apex; while the former (fig. 37; R.Gas.A.)
crosses the corresponding vein and continues parallel with it
along the right and dorsal side of the stomach to the apex. From
the right gastric the posterior gall-bladder artery is given off to
supply the posterior two thirds of the bladder, and a small branch
is also given off to a gland-like body marked G. Intestinal
artery,,, (fig. 37; Int.A.,,)) crosses over the right portal and con-
tinues caudad to the right of intestinal vein,,). Directly in front
of the spleen this artery divides into a dorsal and a ventral ves-
sel. The dorsal artery (fig. 37, Int.A.(,,)) passes to the right
of the spleen, gives off the splenzc artery (fig. 37; Spl.A.) to
the spleen, and crossing the intestinal vessels,,, continues caudad
along the posterior horn of the iliac loop; giving off numerous
branches to the anterior horn and the posterior end of the in-
testine, and finally terminates on the dorsal side of the rectum.
The ventral branch (fig. 37; Int.A...,)) passes ventrad and to
the left of the spleen. Opposite the spleen it sends off the
posterior gastric artery (fig. 37; P.Gas.A.), which crosses the
ceca behind the corresponding vein, and supplies the posterior
or cardiac end of the stomach. The main ventral intestinal
vessel continues along the lower side of the posterior end of
the intestine and terminates on the ventral side of the rectum.
Immediately after leaving the main trunk the celzac artery
(fig. 37; Coe.A.) gives off the right hepatic artery (figs. 37
and 38; R.Hep.A.), which after crossing the ceeliac and right
portal sends off branches along the radicals of the right portal
to the right lobe of the liver, and also gives off the anterzor
gall-bladder artery, which supplies the anterior third of the
bladder, and does not anastomose with the posterior gall-
bladder artery. Passing beneath intestinal vessels,,, the cceliac
artery gives off a rather large left hepatic artery (figs. 37 and
38; L.Hep.A.), which follows along in front of the left portal,
giving off numerous branches to the left lobe of the liver, which
penetrate the liver with the large radicals of the common por-
tal; while none of the branches of the left hepatic anastomose
with similar branches of the right hepatic, several of them send
up branches that supply the ventral portion of the stomach.
Shortly after the branching off of the Jeft hepatic from the

118 ALLEN

ceeliac, intestinal artery.) is given off to the right (fig. 37;
Int.A.(.)); passing caudad to the right of the corresponding
vein it crosses under the ventral branches of intestinal vessels,,),
the spleen, and the dorsal branches of intestinal vessels, and
continuing caudad between the anterior and posterior horns of
the iliac loop, supplies both of them. The cceliac artery proper
separates into the réght and left pyloric ceca arteries. The
former (fig. 37; R.Ca.A.) passes around the pylorus on pyloric
cecum,,), and bifurcates into a dorsal and a ventral branch;
the ventral branch gives off a large branch which crosses under
this cecum, and continues caudad between caecum, and
cecum), giving off branches to each. The left pyloric ceca
artery (fig. 37; L.Cz.A.) passes to the left of the pylorus be-
tween cecum, and czecum,), giving off branches to each.

Portal System.— As in Sebastodes the 2 portals unite in
forming a common portal, that breaks up into numerous
radicals.

The right portal (fig. 37; R.Por.V.) has its origin from the
right gastric, and intestinal vein,,. Jntestznal vein, (fig. 373
Int.V.,,)) arises from a dorsal anda ventral branch. The former
(fig. 37; Int.V..,,)) arises from the dorsal side of the rectum,
and runs cephalad, parallel to the corresponding artery, but
below it; receiving branches from the posterior end of the
intestine and anterior horn of the iliac loop, it crosses intestinal
vessels, and passes above and to the right of the spleen from
which it receives the splenzc vein (fig. 37; Spl.V.). Directly
in front of the spleen the dorsal intestinal vein receives the
ventral intestinal branch (fig. 37; Int.V.,,,.), which arises from
the lower side of the rectum and passes forward along the ven-
tral side of the corresponding artery. Curving around the ven-
tral and left side of the spleen it receives two branches; the first
one, which is the posterzor gastric vein (fig. 37; P.Gas.V.)
arises from the cardiac end of the stomach, and runs along in
front of the posterior gastric artery; while the anterior vessel
has its source from two branches, one coming from between
pyloric cxcay), gq, and the other from-icecum).\jeaater
receiving these branches the ventral intestinal branch crosses
over intestinal vessels,,., and in front of the spleen unites with

BLOOD-VASCULAR SYSTEM OF THE LORICATI I19

the dorsal intestinal branch to form main zutestznal vern.,),
which shortly joins the rzght gastric vern (fig. 37; R.Gas.V.)
to form the vzght portal. This trunk (fig. 37; R.Por.V.)
passes under intestinal artery;,,, and when the right lobe of the
liver is reached, sends off a branch to it, and anastomoses with
the left portal to form the common portal. The branch to the
right lobe of the liver receives the gall-bladder vetn (fig. 37 ;
G.BI.V.), which drains the entire bladder, and receives a
branch from a gland-like body marked G.

The left portal vein (fig. 37; L.Por.V.) has its origin from
intestinal vein ,,, and two pyloric ceca veins. Jntestinal vern .,)
(fig. 37; Int.V.,,) arising from the iliac loop passes cephalad
below the corresponding artery, and after crossing under the
dorsal branch of intestinal vein,,,, the spleen, and the ventral
branch of intestinal vein ,,, it receives a vessel coming from the
dorsal surface of pyloric cecum ,,, designated as the rzght
pyloric ceca ver (fig. 37; R.Ce.V.), and later the left pyloric
ceca ven (fig. 37; L.Cz.V.), which arises from between the
fourth and fifth pyloric ceca. The left portal thus formed
curves around on the dorsal surface of the liver and anastomos-
ing with the right portal forms the common portal trunk (fig.
38; C.Por.V.), which gives off several terminal branches or
radicals to the liver. Into this common portal is poured a rather
large ventral gastric vein (fig. 38; V.Gas.V.), which may to’
some extent take the place of the absent left gastric vein found
in Ophiodon.

The dorsal aorta presents no peculiarities, except that there
are a great number of spermatic arteries (fig. 373; Sper-A.),
usually g or 10.

Renal Portal System.—In the kidney there is a complete
renal portal system. The caudal vezn (fig. 37; Cau.V.) runs
along the left dorsal surface of the kidney as the renal portal
vein, giving off large afferent renal verns (fig. 37; A.Ren.V.)
to each side; while the much smaller efferent renal verns (fig.
37; E.Ren.V.) return the blood to the zght cardinal. 'This
trunk receives, directly, 9 or 10 spermatic veins (fig. 373
Sper.V.) from the reproductive organs. The cntercostal veins
(fig. 37; Intc.V.), however, do not empty directly into the
cardinal, but reach it through the efferent renal veins.

I20 ALLEN

From the previous description it would seem that the vascular
system of Anoplopoma exhibits many points of resemblance to
the more generalized Teleosts. The external carotid, hyoidean,
subclavian, hypobranchial, and coronary trunks appear to have
a more primitive arrangement than is even shown in Sedastodes.

IX. GENERAL CONSIDERATIONS AND SUMMARY.

Since it is almost impossible to determine whether certain
variations in the blood vessels are primitive or secondary it is
not the intention of this paper to draw any conclusions as re-
gards the classification of this group on the basis of the circu-
latory system, until after the anatomy of the other systems has
been worked up. Still it is thought, although perhaps not
practicable, that the vascular system might be used in the class-
ification of families and genera, but could not be used in the
discrimination of species. In the genus Sedastodes a great
number of species were studied, both generalized and special-
ized, but no more variation was noticed in different species than

-could be found among individuals of the same species.

Several interesting anastomoses were noticed in both the
arterial and venous systems. In Ofphzodon we have in the re-
gion of the nasal sac a union of a branch of the internal carotid
with one of the external carotid. The hyoidean artery anas-
tomoses with the main stem of the external carotid to form the
mandibular artery. A branch of the ventral artery joined one
of the subclavian in the pectoral fincanal. The anterior spinal
artery, a branch of the subclavian, united in the neural canal
with the myelonal artery, a branch of the internal carotid.
Two gall-bladder arteries unite on the surface of the bladder.
Usually the posterior mesenteric artery communicates with in-
testinal artery,, and there are connecting arteries between the
right pyloric czeca artery and intestinal artery,,. In Sebastodes
the two anterior spermatic arteries unite with the posterior or
spermatic artery proper. In Hexagrammos the two hepatic
arteries anastomose. In Azoplopoma the hyoidean arteries
anastomose with the pseudobranchial arteries, and the hypo-
branchial arteries unite with the anterior ventral artery. Among
the veins in Ophzodon there is an anastomosis under the nasal

BLOOD-VASCULAR SYSTEM OF THE LORICATI I21

sac of a branch of the internal jugular with one of the external
jugular. A sinus-like vessel connects the two internal jugulars
in the eye-muscle canal. A small vein connects the posterior
encephalic veins directly behind the cerebellum. The ventral
intercostal veins anastomose dorsally with the main intercostal
veins. The gall-bladder veins unite on the surface of the blad-
der, and there are connecting vessels between the right pyloric
ceca vein and intestinal vein,,. There is always some communi-
cation between the two portals: either they terminate in a com-
mon portal as is the case with Sebastodes and Anoplopoma, or
terminal branch (a) of the left portal unites with the right portal
as in Hexagrammos, or else there is a connecting vein in the
neighborhood of the spleen as in Ophzodon and Scorpenichthys.
If a posterior mesenteric vein is present as in Ophzodon and
Scorpenichthys there is a grand anastomosis on the posterior
or cardiac end of the stomach of branch Z of the posterior
mesenteric with the right, left, and posterior gastric veins ; and
branch Y of the posterior mesenteric, usually, anastomoses with
intestinal vein,,. The anterior spermatic veins in Sebastodes
unite with the posterior or spermatic vein proper, and in Scor-
penichthys the left gastric vein anastomoses with the ventral
gastric vein.

In all the specimens studied there was the so-called choroid
gland in the eye, a double vaso-ganglion or retia mirabilia, and
a double retia mirabilia is also present in the air-bladder of
Sebastodes.

The arrangement of the vascular and the blood vessels in the
pseudobranchial filaments is essentially the same as in the
branchial filaments, and it seems reasonable to suppose that the
arterial blood for the eye receives additional oxygen in its course
through the pseudobranchial capillaries.

Summary of the Arteries.—The carotids in all species
studied, but Anxoplopoma, rise from a common trunk, which
soon separates into the external and internal carotids. In
Anoplopoma each of the carotids rises directly from the first
efferent branchial artery. In every case the internal carotid
divides into the orbito-nasal and encephalic arteries. In all the
genera but Anoplopoma the main stem of the external carotid

I22 ALLEN

unites with the hyoidean artery to form the mandibular artery,
but in this genus the hyoidean artery branches in the region of
the preopercle. The ventral fork passes through a foramen in
front of the preopercle to become the mandibular artery; while
the dorsal fork passes along the inner surface of the hyomandib-
ular and anastomoses with the pseudobranchial artery. Usu-
ally the pseudobranchial artery has its origin from the main
stem of the external carotid (facialis-mandibularis) in the facial
region, but with Axoplopoma the pseudobranchial artery rises
from the external carotid close to its origin from the first effer-
ent branchial artery; in fact it might be said to rise with the
external carotid from the first efferent branchial artery, being
fully as large as the carotid. An ophthalmic or efferent pseudo-
branchial artery always rises from the efferent pseudobranchial
arteries, which supplies only the choroid coat of the eye. In
Ophiodon the ventral artery rises from the ventral union of the
second and third pairs of efferent branchial arteries; while in
the other genera it comes from the union of the second efferent
vessels. This artery in Anoplopoma is a short vessel barely
reaching the pelvic bones; the supply for the ventral fin region
comes from the subclavian. In all the genera but Anoplopoma,
the pharynx artery, from which the coronary rises, has its
source directly from one of the second or third efferent bran-
chial arteries, but in this genus it rises from the ventral artery.
There is always a distinct circulus cephalicus formed by the
union of the encephalic, internal carotid, common carotid, first
efferent branchial, and the first epibranchial arteries. Both
pairs of epibranchials terminate in a common chamber from
which the dorsal aorta, cceliaco-mesenteric, and subclavians
have their origin; in some cases, however, this chamber is
simply an opening between the aorta and the cceliaco-mesen-
teric. The dorsal aorta is essentially the same in all the gen-
era; passing caudad beneath the vertebral column it gives off
the renal and spermatic arteries to the kidney and the reproduc-
tive organs, the neural, hemal, and intercostal arteries to the
body wall, and finally terminates in the caudal fin. The sub-
clavian arteries are practically the same in all the forms studied ;
they may arise from a single trunk or separately as was de-

BLOOD-VASCULAR SYSTEM OF THE LORICATI 123

scribed under Ophzodon, or they may arise from the dorsal
aorta as in Anoplopoma. In the case of Anoplopoma a rather
large hypobranchial artery is given off, which anastomoses with
the anterior ventral artery, and the right hypobranchial sends
off the posterior ventral artery for the ventral fin region. The
ceeliac artery always supplies the pyloric ceca. With Opfhzo-
don, Sebastodes, and Anoplopoma it is the source of the left hepa-
tic artery, and in Ophiodon, Hexagrammos, and Anoplopoma
it gives off intestinal artery... From the mesenteric artery, in-
testinal artery,, the splenic and 2 gastric arteries have their
origin. In Hexagrammos and Scorpenichihys the right gastric
is the source of the left hepatic artery, and in Sedaséodes it is
the source of the right spermatic and the anterior air-bladder
arteries, the left spermatic artery coming from the left gastric
artery. In Scorpenichthys the entire intestinal supply comes
from the mesenteric artery.

Summary of the Verns. —'The jugular and its branches are
essentially the same in all the species studied, receiving the
mandibular, hyoidean, maxillary, orbito-nasal, ophthalmic, eye-
muscle, and encephalic veins. In addition to the main inferior
jugular and the left fork there are additional veins from the
pharynx regionin Sedastodes, Scorpenichthys, and Anoplopoma,
which empty into the precava. Considerable variation is shown
in the subclavian veins. ‘There is always an external and an
internal subclavian, and in Scorpenichthys there are several
internal subclavians. Ordinarily the internal subclavian breaks
up in the corresponding fork of the kidney, and the external
subclavian empties into the precava, but in Scorpenichthys the
external subclavian also breaks up in the kidney, while in
Anoplopoma the external subclavian appears to penetrate the
scapula foramen with the corresponding artery, uniting with the
internal vein to form a common trunk, which breaks up in the
kidney. Usually there are 2 ventral veins of equal size, but
in Ophiodon one of them is often much the larger, draining the
entire ventral fin region. There is always a distinct renal portal
system. The caudal vein arises in the tail and passing forward
in the hemal canal below the aorta, receives the neural and
hzmal veins, and upon entering the kidney, usually, bifurcates

124 ALLEN

into the renal portal veins. With Sedastodes these veins extend
much further cephalad than in the other genera, and in Opfhzo-
don and Scorpenichthys the caudal vein receives the posterior
mesenteric vein immediately after entering the kidney. It is of
interest to note in connection with the posterior mesenteric vein,
that in 2 other genera of the Cottoids, namely, Calyczlepidotus
and Enofhrys, this vessel was absent. The right cardinal
always arises in the caudal end of the kidney and drains the
entire kidney, while the left cardinal drains only a portion of
the left lobe of the kidney. The intercostal and the anterior
neural veins break up in the kidney. ‘The spermatic veins vary
greatly in size, number, and position; with the female they
arise from numerous branches, passing along the lateral surfaces
of the ovaries; while in the male these branches come from the
inside of the testes, and the spermatic veins terminate in the
right cardinal or the renal portal veins. The cardinals and
jugulars always unite on the ventral surface of their respective
lobe of the kidney to form the precava, which pass around the
cesophagus and terminate in the sinus venosus. There is always
a distinctive hepatic portal system, which takes its origin from
a right and a left portal vein. Usually the left portal vein has
its source from 2 pyloric ceca veins, an intestinal, and a few
ventral gastric veins. In Scorpenichthys it receives the entire
intestinal supply. The right portal ordinarily arises from a
right gastric, an intestinal, and a splenic vein; in Scorpe-
nichthys no intestinal vein is received; while in Sebastodes the
right gastric branch receives the additional anterior air-bladder
vein. In Ophiodon, always, and in Scorpenichthys, usually,
the 2 portals have no connection within the liver; while with
flexagrammos a branch of the left portal anastomoses with the
right portal; and in Sebastodes and Anoplopoma the 2 portals
and several minor vessels empty into and form a common portal.
As in other vertebrates the portals break up into venous capil-
laries within the liver, and become collected by 2 hepatic
veins, which unite in a hepatic sinus before emptying into the
sinus venosus. An interesting vein in Ophdodon and Scorpe-
nichthys is the left gastric vein, which arises from the left side
of the stomach and empties directly into the precava. With the

BLOOD-VASCULAR SYSTEM OF THE LORICATI I25

other genera this region is drained by enlarged ventral gastric
veins, that empty into the left portal.

X. BRIEF SYNONYMY OF THE BLOOD VESSELS.

1. Afferent branchial artery, A.Br.A. Branches of the
branchial artery, Monroe; Rameau (3), C. & V. Kiemenar-
terien, Hyrtl; Muller, and Stannius; Arterie branchiali,
Emery; Arteria branchiales, McKenzie; Afferent branchial
arteries, Parker; Kiemenarterien, V. & Y.!

2. Afferent filament arteries, A.Fil.A. Une branche (z) a
chacun de ces feuillets, C. & V. Ast der Kiemenarterie, Mil-
ler; Desc. by Stannius; (e) fig. 318, Owen; Branches of the
afferent artery.) batker:) Desc. V.i& Y.

3. Afferent renal veins or Advehent renal veins, A.Ren.V.
Vene renalis advehens, Stannius ; Vena aveente renale, Emery ;
Vena renalis advehens, McKenzie; Afferent renal veins,
Parker.

4. Azr-bladder retia mirabilia artery or Anterior atr-blaa-
der artery, A.B].A. Desc. Stannius; Branch of celiac to air-
bladder, Owen; Desc. and fig. Emery; Desc. McKenzie;
Artery to rete mirabile, Parker; Arterie der Schwimmblase,
ViPS VG .

5. Arr-bladder retia mtrabilia vein or Anterior air-bladder
vein, A.B1.V. Desc. Stannius; fig. Emery; Vessels from rete
mirabile, Parker; Schwimmblasenvene, V. & Y.

6. Aur7cle, Aur. Oreillete, C. & V. Vorkammer, Miiller,
Stannius, and V. & Y. Auricle, Owen and Parker; Atrio,
Emery; Atrium, McKenzie.

7. Bulbus arteriosus, B.Art. Bulbe (y), C. & V. Bulbo
aortico, Emery; Bulbus arteriosus, Hyrtl, Miiller, Stannius,
Owen, McKenzie, Parker, and V. & Y.

8. Caudal artery, Cau.A. Caudal aorta, Hyrtl; Arteria
caudalis, Miller, Stannius, and McKenzie; Caudal artery,
Parker; Bauchaorta, V. & Y.

9. Caudal vein, Cau.V. Veins from the tail, Monroe; Vena
caudalis, Hyrtl. Miiller, and Stannius; Vena cardinalis, Owen ;

1 Abbreviations C. & V. stand for Cuvier and Valenciennes, V. & Y. for Vogt
and Yung, and Desc. for described. i

126 ALLEN

Vena codale, Emery; Vena caudalis, McKenzie; Caudal
vein, Parker.

10. Celiac artery, Coe.A. An artery like unto our cceliac,
Monroe; Arteria cceliaca, Hyrtl and Stannius; Cceliac,
Owen; A. Mesentertca inferiore Emery (?); Cceliac artery,
Parker.

11. Celiaco-mesenteric artery, Coe.Mes.A. Arteria cceliaco-
mesenterica, Hyrtl, Stannius, and McKenzie; Arteria ceeliaca,
Emery (?); La grande artére aux viscéres (7), C. & V. Ce-
liaco-mesenteric artery, Owen; Cceliaco-mesenteric artery,
Parker; Baucharterie, V. & Y.

12. Common carotid arteries,C.Car.A. Les artéres de la téte
(s), C. & V. Carotis communis, Stannius; Kopfarterien, V. &
Y. Common carotid arteries, Parker.

13. Coronary artery, Cor.A. Coronary artery, Monroe;
Fig. C. & V. Kranzarterie, Hyrtl and Miiller; Coronary
artery, McKenzie and Parker.

14. Coronary veins, Cor.V. Coronary veins, Monroe and
Parker.

15. Dorsal aorta, D.Ao. ‘Trunk of descending aorta, Mon-
roe; Aorte, C. & V. Aorta, Hyrtl, Miller, Owen, Emery,
V.& Y. Aorta decendens, McKenzie; Dorsal aorta, Parker.

16. Lfferent branchial arteries, E.Br.A. Branchial veins,
Monroe; La grande véine de la branchie (A), C. & V. Kiemen-
venen, Hyrtl, Miller, Stannius, and V. & Y. Vene branch-
iali, Emery; Venz Branchiales, McKenzie; Efferent branchial
arteries, Parker.

17. Efferent filament arteries, E.Fil.A. Une veine branch-
iale (#), C. & V. Ast der Kiemenvene, Miller; Desc. Stan-
nis; (d) ie. 21s. Owens Dese. McKenzie, and mV. aay
Branches of the efferent arteries, Parker.

18. Afferent renal veins or Revehent renal ves, E.Ren.V.
Venez renales revehentes, Stannius; Vena reveente, Emery.

19. Encephalic artery or Brain artery, Enc.A. Zweige
zum Hirn, Miller; Hirnarterie, Stannius; Encephalic arteries
(3), McKenzie, Cerebral artery, Parker; Hirnarterie, V. & Y.

20. Encephalic vein, Enc.V. Desc. by Stannius; Desc. and
fig. by Emery; Anterior cerebral vein, Parker.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 1p

21. Epibranchial arteries, Epbr.A. (yu), C. & V. Aorten-
wurzeln, Hyrtl; Venez branchiales communes, Miller; Epi-
branchial arteries, Parker.

22. External carotid arteries or posterior carotid arteries,
E.Car.A. Arteries sent to jaws, Monroe (?); Carotis externa,
Hyrtl and McKenzie; Carotis posterior, Miller and Stannius ;
Carotids, Owen; Carotide posteriore, Emery; Posterior carot-
ids, Parker; Gesichtsarterie and Arteria facialis, V. & Y.

23. External jugular or factal veins, Ex.J.V. Desc. by Stan-
nius; Anterior facial veins, Parker; Gesichtsvene or Vena
facials, Vis Gea) Xv

24. flemal artertes, Hae.A. Heemal arteries, Owen and
McKenzie; Kio. ©. & V..andi V. ic Yj:

25. Haemal veins, Hae.V. Hemal veins, Owen and Mc-
Kenzie; Fig iCy ci Va and Vo a Y.

26. Hepatic stnus, Hep.S. and Hepatic vers, Hep.V. Venae
cava Hepaticae, Monroe; Les venes du foie, C. & V._ Leber-
vene, Miiller and Stannius; Hepatic vein, Owen and McKen-
zie; Hepatic veins and sinus, Parker; Lebervene, V. & Y.

27. Hyotdean artery, Ayo.A. Fig.C.&V. Arteria hyoideo-
opercularis, Miller; Arteria hyoidea, Stannius ; Hyo-opercular
artery, Owen; Arteria, ioidea, Emery ; Hyoidean artery, Parker.

28. Hyotdean vein, Hyo.V. Vena ioidea, Emery; Hyoi-
dean sinus, Parker (?).

29. Hypobranchial artery, Hypobr.A. Fig. by Monroe;
Desc. by McKenzie; Hypobranchial artery, Parker.

30. Lnfertor jugular vein, 1. J. V. External jugular vein,
Monroe; Vena jugularis inferior, Miller, Stannius, and Mc-
Kenzie; Inferior jugular vein, Parker.

31. Lnnerirts vein, 1.Ir.V. Die innere Vene der Iris, Miller.

32. Intercostal arterzes, Inte/A. )Axrterice intercostales,
Hyrtl, Miller and Stannius; Intercostals, Owen and McKen-
zie; Intervertebrale este V. & Y.

33. Lntercostal veins, Intc.V. Venez intercostales, Miller
and McKenzie; Intercostal veins, Parker.

34. Lnternal carotid artery, I.Car.A. Retrograde artery
(€), Monroe (?); Carotis anterior, Miller and Stannius; Car-
otis interna, Hyrtl and McKenzie; Carotide anteriore, Emery ;
Anterior carotid artery, Parker; Einen tieferenStamm, V.& Y.

128 ALLEN

35. Lnternal jugular veins, In.J.V. Vena jugularis interna,
Miller.

36. Lnternal subclavian arterves, 1.Sub.A. Arteria branch-
ialis, Stannius; Branchial artery, Parker.

37. Lntestinal artery (1), Int-A. (1). Arteriz intestinales
mesenterica, Stannius; Posterior mesenteric artery, Owen;
Mesenterica superiore, Emery (?); Mesenteric artery, McKen-
zie; Dorsal intestinal artery, Parker (?); Duodenalarterie, V.
Sai)

38: /ulesienal artery (2) intA.(2). Big. C. & VV. Arter-
iz intestinales cceliaco, Stannius; Ventral intestinal artery, Par-
keris); Darmarterte, V sc2) Y¥.:(0),

39. Lntestinal ven (1), Int.V.(1). Darmvene, Miller; Desc.
Stannius; Fig. Emery; Mesenteric vein, McKenzie; Dorsal
intestinal vein, Parker (?); Darmvene, V. & Y. (°).

40. Intestinal vein (2), Int.V.(2). Ventral intestinal vein,
Parker i(:).

41. Lr¢s artery or Ophthalmic minor artery, Ir.A. Arteria
ophthalmica minor, Miller; Desc. Stannius.

42. Lrts vein or Ophthalmic minor vein, Ir.V. Die aussere
Vene der Iris, Miller; Die Vene der Iris, Stannius.

43. Jugular vein, J.V. Internal jugular vein, Monroe; Les
veines de la téte (w), C. & V.; Vena jugularis superior, Mil-
ler; Vena vertebralis anterior, Stannius; Vena jugularis, Owen;
Vena giugulare, Emery; Anterior cardinals, McKenzie; Jugu-
lar vein, Parker; Jugularvene, V. & Y.

44. Lateral arteries, Lat.A. Arteria lateralis, Stannius ;
Lateral arteries, McKenzie.

45. Lateral veins, Lat.V. Lateral veins, McKenzie.

46. Left cardinal vein, L.Car.V. Abdominal or vena cava,
Monroe; Les veines des reins (#), C. & V.; Vertebralvene,
Miller; Vena vertebralis posterior, Stannius; Vena cardinalis,
Owen; Vena cardinale, Emery; Left cardinal vein, McKen-
zie and Parker; Linke cardinalvene, V. & Y.

47. Left gastric artery, L.Gas.A. Fig. C. & V. and V. &
Y. Anterior gastric artery, Parker (?).

48. Left gastric vein, L.Gas.V. Anterior gastric vein, Par-
enh)

BLOOD-VASCULAR SYSTEM OF THE LORICATI I29

49. Left hepatic artery, L.Hep.A. Small artery resembling
the hepatic artery, Monroe; Desc. by C. & V. and Miiller;
Arteriz hepatice, Hyrtl and Stannius; Hepatic artery, McKen-
zie; Left hepatic artery, Parker; Leberarterie, V. & Y.

50. Mesenteric artery, Mes.A. An artery resembling our
superior mesenteric artery, Monroe; Arteria mesenterica anter-
ior, Hyrtl and Stannius; Arteria celiaca, Emery (?); Mesen-
teric artery, Parker; Baucharterie, V. & Y. (?).

51. Myelonal artery, My.A. Myelonal artery, Parker.

52. Myelonal vein, My.V. Not vena neuralis of Owen;
Myelonal vein, Parker.

53. WVeural arteries, Neu.A. Arteria spinales, Hyrtl; Neu-
ral arteries, McKenzie; Spinal arteries, Parker.

54. WVeural veins, Neu.V. Neural veins, Owen and Mc-
Kenzie; Spinal veins, Parker.

55. LVutrient branchial artertes, N.Br.A. Nutrient branch-
ial arteries, Parker.

56. Wutrient branchial veins, N.Br.A. Venez nutritiz der
Kiemenbogen, Miller; Venz nutritie, Stannius and Owen;
Nutrient branchial veins, Parker.

57. LVutrient filament artertes, N.Fil.A. Bronchialarterien,
Miller; Arteria bronchialis, Stannius; Arteriz nutritize, Owen.

58. WMutrient filament veins, N.Fil.V. Bronchialvenen, Mil-
ler; Vena bronchiales, Stannius.

59. Ophthalmic artery or Efferent pseudobranchial artery,
Oph.A. Arteria ophthalmica magna, Miller and Stannius;
Ophthalmic artery, Owen; Desc. and Fig., Emery; Ophthal-
mica magna, McKenzie; Ophthalmic artery, Parker ; Efferent
pseudobranchial artery, Allis.

60. Ophthalmic vein, Oph.V. Vena ophthalmica magna,
Miller and Stannius; Desc. and Fig. Emery.

61. Optic or Retina artery,Opt.A. Die Gefasse der Retina
und der Hallenschen Gefasse, Miller; Arteria ottalmica,
Emery (?); Optic artery, Allis.

62. Orbito-nasal artery, O.N.A. Zweige zu den Augen-
muskeln und zur Nase, Miller; Arteria etmoidale, Emery ;
Augenarterie, V. & Y.

Proc. Wash. Acad. Sci., June, 1905.

130 ALLEN

63. Orbito-nasal vein, O.N.V. Vena etmoidale, Emery;
Orbital sinus, Parker.

64. Pharynx artery, Phar.A. Pericardial artery, Parker (?).

65. Posterior air-bladder artery, P.A.BI.A. Vena vescicale
posteriore, Emery.

66. Posterior encephalic vein, P.Enc.V. Desc. by Emery;
Posterior cerebral vein, Parker.

67. Posterior or left portal vein, L.Por.V. La veine porte
(4), C& V. Pfortaderstamm, Miller and Stannius; Portal trunk,
Owen; Portal vein, McKenzie; Hepatic portal and Portal vein,
Parker: )Pfortader, Vcc Yi.

68. Precaval vein or Ductus cuviert, Prec.V. Desc. and
figured by Monroe; Trunci transversi, Stannius; Precaval
vein, Owen; Tronco di Cuvier, Emery; Ductus cuvieri, Mc-
Kenzie; Precaval vein, Parker; Ductus cuvieri, V. & Y.

69. Pseudobranchial artery or Afferent pseudobranchial ar-
tery, Ps.A. Part of Arteria hyoideo-opercularis, Muller; Part
of Arteria hyoidea, Stannius; Part of Hyo-opercular, Owen;
Part of Arteria ioidea, Emery ; Pseudobranchial artery, Parker ;
Afferent pseudobranchial artery, Allis.

VO. -ylorecice@cg arlevies,. Ce... Hig. (Cum V1 Wee,
by Stannius, Parker, and V. & Y.

"1. Pyloric ceca ves, R.Cze.V. Fig. C.& V. Desc.-by
Stannius and V. & Y.

42. ftenal Arterzes, Ren.A. Arteria renales, McKenzie;
Renal arteries, Parker; Nieren arterienzweige, V. & Y.

73. Ltenal portal vein, Ren.P.V. Vena renalis advehens,
Stannius; Veine porte rénale, Jourdain; Vena aveente renale,
Emery; Vena renalis advehens, McKenzie; Renal portal vein,
Parker.

74. Light cardinal vein, R.Car.V. Vena vertebralis pos-
terior dextra, Stannius; Venez cardinales, Owen; Vena car-
dinale, Emery; Right cardinal vein, McKenzie and Parker;
Rechte cardinalvene, V. & Y.

75. Right gastric artery, R.Gas.A. Desc. Miiller, Stan-
nius, and McKenzie; Gastric artery, Owen; Fig. and Desc.
Emery; Dorsal gastric artery, Parker (?); Magenarterie,
Wirnec Ne

BLOOD-VASCULAR ‘SYSTEM OF THE LORICATI I31

76. Fight gastric vein, R.Gas.V. Desc. Stannius; Fig.
Emery; Gastric vein, McKenzie; Anterior lieno-gastric vein,
Parker (7); Deses and Hig. Vo & Y.

"7. Right hepatic artery, R.Hep.A. Ejinen fir jeden
Leberlappen, Miller; Arteriz hepatice, Stannius, Right
hepatic artery, Parker; Leberarterie, V. & Y.

VOI SCnUsEBOsUS. 510. V en. | Sinus; \vemmeux, | (Cy Vai
Sinus venosus, Stannius, Hyrtl, Owen, McKenzie, and
Parker; Sinus communis, Miller; Venensinus, V. & Y.

79. Spermatic artery, Sper.A. Fig. C. & V. Genitalarterie,
Miiller and V. & Y. Desc. Stannius; Fig. Emery and C. & V.
Genital artery, McKenzie; Spermatic artery, Parker.

80. Spermatic vein, Sper.V. Les veines des organes de la
génération (g), C. & V. Genitalvenen, Miller and V. & Y.
Desc. Stannius; Fig. Emery; Genital veins, McKenzie;
Spermatic veins, Parker.

Ob. Oplente artery Splat Hig. ©. & V. and, Emery ;
Desc. Stannius and Owen; Splenic artery, McKenzie and
Parker; Desc and His. by Vi. & Y.

62. Splenic vem, spl. V “Big. C. & Vand) Emery ;' Desc:
Stannius; Vein from spleen, Owen; Splenic vein, McKenzie
and. Parker; Descand Bie. V. a Y.

83. Subclavian artery, Sub.A. Subclavian artery, Monroe,
Owen, McKenzie, and Parker; Arteria subclavia, Miiller,
Hyrtl, and Stannius; Arterie ascellari, Emery; Schulter-
arterie, V. & Y.

84. Subclavian veins (1), (2), and (3), Sub.V. (1) to (3).
Subclavian vein, Monroe and Parker; Vena subclavia, Stan-
nius; Includes the branchial vein of Stannius and Parker;
Schultervene, V. & Y.

85. Thyroid artery, Thyr.A. Thyroid artery, McKenzie.

86. Urinary bladder artery and vein, Ur.B.A. and Ur.B.V.

Bisa CSV cand, Vince Y:
' 87. Ventral aorta or Branchial artery, V.Ao. Branchial
artery, Monroe and Owen; L’artére branchiale (¢), C. & V.
Arteria branchialis, Miller; Kiemenarterienstamm, Stannius ;
Cardiac aorta, Huxley; Truncus arteriosus, McKenzie; Tronco
dell’aorta, Emery ; Gemeinsame Kiemenarterie, V. & Y.

032 ALLEN

88. Ventral artery, Ven.A. Ramus epigastricus decendens,
Miller (?); Arteria epigastrica, Stannius; Fig. C. & V.
Artery supplying the pelvic fins, Parker.

89. Ventral intercostal arteries, V.Intc.A. Fig. C. & V.
Arteriz intercostales ventrales, Miiller.

90. Ventral intercostal veins, V.Intc.V. Fig. C. & V.
Vena intercostales ventrales, Miiller.

91. Ventral veins, Ven.V. May be homologous to the epi-
gastric veins of Miller and Stannius.

92. Ventricle, Ven. Ventricule, C. & V. Herzkammer,
Miiller, Stannius, and V. & Y. Ventricolo, Emery; Ventricle,
Owen, McKenzie, and Parker.

XI. BIBLIOGRAPHY.
1. Albers.
1806 Title not known. Gédtting. gel. Anz., 1806.
2. Agassiz et Vogt.
1845 Anatomie des Salmonés. Mémoires dela Société des Science naturelles
de Neuchatel, 1845.
3. Allis, E. P.
1897 Cranial Muscles and Cranial and First Spinal Nerves in Amia calva.
< Journ. of Morph., Vol. 12, 1897.
4. Allis, E. P.
1900 Pseudobranchial Circulation in Amia calva. < Zool. Jahrb., Oct.,
1900.
5. Bau, K. E.
1834 Ueber das Gefadsssystem der Braunfische. < Abhandlyn. der Berl.
Akad., 1834.
6. Bonsdorf, E. J.
1851 Portven Systemet hos Gadus Lota. Helsingf., 1851.
7. Boas, J. E. V.
1880 Ueber Hertz und Arterienbogen bei Ceratodus und Protopterus
< Morph. Jahrb., Bd. 6, 1880.
8. Boas, J. E. V.
1887 Ueber die Arterienbogen der Wirbelthiere. < Morph. Jahrb., Bd. 13,
1887.
g. Bietrix, E.
1895 Etude de quelques faits relatifs a la morphologie générale du systeme
circulatoire. Paris, 1895, Abstr. in Zool. Jahrb.
1o. Briinnings, W.
1900 Zur Physiologie des Kreislaufe der Fische. Archiv f. Phy., 1900.
11. Cuvier et Valenciennes.
1828 Histoire Naturelle des Poissons. Paris, Vol. 1, Pls. 7 and 8, 1828.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 133

12. Cunningham, J. T.
1890 A Treatise on the Common Sole. Plymouth, 18go.
13. Duverney, M.
1699 Structure du Coeur des Poissons. Hist. de l’Acad. des Sci. de Paris,
1699. Also reprint in Artedi Bibliotheca Ichthyologica, 1788.
14. Duverney, G. J.
1701 Mém. sur la circulation du Sang des Poissons. Mém. Acad. Sci. Paris,
17o1. Also reprint in Artedi Bibliotheca Ichthyologica, 1788.
15. Déllinger, J.
1811 Ueber den eigentlichen Bau des Fishherzens. Annal. d. Welter.
Gesellsch. f. d. ges. Naturkunde, 1811.
16. Dollinger, J.
1831 Ueber die Vertheilung des Blutes in den Kiemen der Fische. Aus den
Abhandlyn. d. Kénigl. Bayer Akad. der Wissensch., 1831.
17. Demme, R.
1860 Gefisssystem von Acipenser rethenus. Wien., 1860.
18. Denissenko, G.
1880 Mittheilung iiber die Gefiasse der Netzhaut der Fishe. Arch. f. Mik.

Anat., 1880.
1g. Dean, B.
1895 Fishes, Living and Fossil. Columbia University Biol., Ser. 3, 1895.
20. Dohrn, A.

Various papers in Mitth. Zool. Stat. Neapel, Bd. 6, 10, II and 15.
21. Eichwald.
1819 De Selachis Aristotelis. Vilnz, 1819.
22. Eschricht, D. F.
1857 Ueber die Wundernetze an den Leber des Thunfisches. Aus den Ab-
handlyn. der Berlin Akad., 1857.
23. Milne Edwards, H.
1859 Lecons sur la Physiologie et Anatomie. Paris, 1859.
24. Emery, C.
1880 Fierasfer. Reale Accademia dei Lincei. Roma, 1880.
25. Fohmann, V.
1827 Das Saugadersystem der Wirbelthiere. Heidelberg’u. Leipzig, 1827.

26. Gegenbaur, C.
1866 Zur vergleichenden Anatomie des Herzens. Jen. Zeitsch. f. Naturw.,
Bd. 2, 1866.
27. Gegenbaur, C.
1870 Grundziige der vergleichenden Anatomie. Leipzig, 1870. Eng. Trans.
F. J. Bell, London, 1878.

28. Gegenbaur, C.
1891 Ueber, den Conus Arteriosus der Fische. Morph. Jahrb., Oct. 1891.

29. Hall, M.
1831 Critical and Experimental Essays on the Circulation of the Blood in
Minute Capillary Vessels of Batrachia and Fishes. London, 1831.

134 ALLEN

30. Hyrtl, J.
1838 Ueber das Gefiisssystem der Fische. Med. Jahrb. d. dsterr. Staates,
Bd. 15, 1838.
ein dehpadls |e
1843. Ueber die Caudal und Kopf-Sinuse der Fische, und das damit zusam-
menhingende Seitengefass-System. Arch. f. Anat. u. Phys., p. 224,
1843.
32. Hyrtl, J.
1852 Ueber das Arterien-System des Lepidosteus. Wirklichem mitgliede
der Kais. Akademie der Wissenshaften, Bd. 8, 1852.
33- Hyrtl, J.
1853 Anatomie yon Saccobranchus Singio. Wirkl. mitg. d. Kais. Akad. d.
Wissensch., Bd. 9, 1853.
34. Hyrtl, J.
1858 Das arterielle Gefass-System der Rochen. Denk. Akad. Wien., Bd. 15,
1858.
35. Hyrtl, J.
1869 Ueber die Blutgefasse der 4usseren Kiemendeckelkieme von Polypterus
Lapradei. Wirkl. mitg. d. Kais. Akad. d. Wissensch., 1869.

36. Hewson, W.
1869 Lymphatic System of Fish. Phil. Trans., Vol. 59, 1869.
37. Hyrtl, J.
1871 Die Kopfarterien der Haifische. Denk. Akad. Wien, Bd. 32, 1871.
38. Hochstetter, F.
1887 Beitrage zur vergleichenden Anatomie und Entwickelungsgeschichte
des Venensystems der Amphibien und Fische. Morph. Jahrb., Bd. 13,
1887.
39. Hoffman, C. K.
1893 Zur Entwicklungsgeschichte des Herzens und der Blutgefasse bei den
Selachiern. Morph. Jahrb., Bd. 19 und 20, 1893.

40. Hopkins, G. S.
1893 Lymphatics and Enteric Epithelium of Amia calva. Wilder Quarter
Centuary Book, Ithaca, 1893.
41. Jones, W.
1838 Title not known. London Med. Gazette, p. 650, Jan., 1838.
42. Jourdain, S.
1859 Recherches sur la Veine Porte Rénale. Ann. des Sci. Nat., Tome 12,
1859.
43. Jones, T. W.
1868 The Caudal Heart of the Eel a Lymphatic Heart. Phil. Trans., 1868.

44. Jordan and Gilbert.
1883 Synopsis of Fishes of North America. Bull. 16, U. S. Nat. Mus.,
1883.

45. Jordan and Evermann.
1898 Fishes of North and Middle America, Vol. 2. Bull. 47, U. S. Nat.
Mus., 1898.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 135

46. Kasem-Beck und Dogiel.
1882 Beitrag zur Kenntnis der Structur und der Function des Herzens der
Knochenfische. Zeitschr. f. Wiss. Zool., 1882.
47. Lankester, E. R.
1879 Hearts of Ceratodus, Protopterus, and Chimera, Trans. Zool. Soc.
London, Vol. 11, 1879.
48. Monroe, A.
1787 Vergleichung des Baues und der Physiologie der Fische. Leipzig,
1787.
49. Monroe, A.
1788 A Description of the Heart and Circulation of Blood in Fishes. Artedi
Bibliotheca Ichthyologica, p. 184, 1788.
50. Miiller, J.
1839 Ueber das Gefiisssystem der Fische. Abhandl. d. Berlin Akad., 1839.
Also vol. 4, Vergleichende Anatomie der Myxinoiden. Berlin, 1841.
51. Maurer, F.
1883 Ein Beitrag zur Kenntnis der Pseudobranchie der Knochenfische.
Morph. Jahrb., Bd. 9, 1883.
52. McKenzie, T.
1884 Blood Vascular System of Amiurus Catus. Proc. of the Canadian Inst.,
1884.
53. Marshall and Hurst.
1886 Practical Zoology. New York and London, 1886.
54. Mayer, P.
1887 Ueber die Entwickelung des Herzens und der grossen Gefissstamme
bei den Selachiern. Mitth. Zool. Stat. Neapel., Bd. 7, 1887.
55. Mayer, P.
1888 Ueber Eigenthiimlickeiten in den Kreislaufsorganen. Mitth. Zool. Stat.
Neapel., Bd. 8, 1888.
56. Maurer, F.
1888 Die Kiemen und ihre Gefiasse bei Anuren und Teleostieren. Morph.
Jahrb., Bd. 14, 1888.
57. Miiller, F. W.
1897 Ueber Entwickelung und Morphologische Bedeutung der Pseudobranchie
und ihre Umgebung bei Lepidosteus Osseus. Arch. f. Mik. Anat.
Vol. 49, 1897.
58. Owen, R.
1866 Anatomy and Physiology of Vertebrates. London, Vol. 1, 1866.
59. Parker, T. J.
1880 On the Venous System of the Skate, Raja Nasuta. Trans. of the N.
Zealand Inst., Vol. 13, 1880.
60. Parker, T. J.
1886 Blood Vessels of Mustelus Antarticus. Phil. Trans. of the Roy. Soc.
London, p. 685, 1886.
61. Parker, T. J.
1895 Zootomy. London, 1895.

136 ALLEN

62. Parker and Haswell.
1897 Text Book of Zoology. London, Vol. 2, 1897.
63. Parker and Davis.
1899 Blood Vessels of the Heart of Carcharias, Raja, and Amia. Proc. of the
Boston Soc. of Nat. His., Vol. 29, 1899.
64. Quekett, J.
1844 On the Arrangement of the Blood Vessels in the Air-Bladder of Fishes.
Trans. of Micro. Soc. of London, Vol. 1, 1844.
65. Quekett, J.
1852 Capillaries in the Gills of Fishes. Trans. of Micro. Soc. of London,
Vol. 2, 1852. Also Vol. 3, 1847.
66. Rathke, M. H.
1826 Ueber die Herzkammer der Fische. Arch. f. Anat. u, Phys., p. 152,
1826.
67. Rathke, M. H.
1826 Ueber die Leber, und das Pfortadersystem der Fische. Arch. f. Anat.
u. Phys., 1826.
68. Robin, C.
1867 Sur les vaisseux lymphatiques des Poissons. Arch. gén. de méd., Par-
tie anatomique, 1845. Also Arch. f. Anat. u. Phys., Bd. 4, 1867.
69. Rattone et Mondino.
1889 Sur la Circulation du Sang dans le Foie. Arch. Ital. de Bio., Vol. 12,
1889.
70. Rose, C.
1890 Beitrage zur vergleichenden Anatomie des Herzens der Wirbelthire.
Morph. Jahrb., Bd. 16, 1890.
71. Raffaele, F.
1892 Ricerche sullo sviluppo del sistema vascolare nei Selacei. Mitth. Zool.
Stat. Neapel., 1892.
72. Ridewood, W. G.
1899 On the Relaltions of the Efferent Branchial Blood-vessels to the Cir-
culus Cephalicus in Teleostean Fishes. Proc. London Zool. Soc., 1899.

73. Schina, A. B. M.
1836 Anatomico fisiologica comparativa del sistema vasale, Torino, Vol. 2,
1836.
74. Stannius, H.
1854 Handbuch der Anatomie der Wirbelthiere. Bd. 1, 1854.

75. Stohr, M. P.
1876 Ueber den Klappenapparat im Conus Arteriosus der Selachier und
Ganoiden. Morph. Jahrb., Bd. 2, 1876.

76. Sappey, P. C.
1880 Etudes sur l’Appareil mucipare et sur le Systtme lymphatique des Pois-
sons. Paris, 1880.
77. Spencer, W. B.
1892 Contributions to our Knowledge of Ceratodus. Macleary Memorial
Vol. Sydney, Part 1, 1892.

#

BLOOD-VASCULAR SYSTEM OF THE LORICATI 11S 7)

78. Shonlein et Willem.
1895 Observations sur la circulation du sang chez quelque Poissons. Bull.
Sci. France Belg., Tome 26, 1895.
79. Tiedermann, F.
1809 Anatomie des Fishherzens. Landshut, 1809.
80. Treviranus, G. R.
1839 Beobachtungen aus der Zootomie und Physiologie. Bremen, 1839.
81. Trois, E. F.
1878 Contribuzione allo studio del sistema linfatico dei Teoleostei. Extr.
degli Atti del R. Istituto Veneto, pp. 1-55. 1878-81.
82. Thesen, J.
1896 Etude zur la biologie du cceur des Poissons osseux. Arch. Zool.
Expér., Tome 4, 1896.
83. Vogt, C.
1842 Embryologie des Salmones. Neuchatel, 1842.
84. Virchow, H.
1890 Ueber die Spitzlochkieme von Acipenser und ihre Verbindung mit den
Kopfgefissen. Arch. f. Anat. u. Phys., 1890.
85. Vogt und Yung.
1894 Lehrbuch der praktischen vergleichenden Anatomie, Bd. 2, 1894.
86. Wiedersheim, R.
1886 Lehrbuch der vergleichenden Anatomie der Wirbelthiere. Jena, 1886.
87. Wiedersheim, R.
1893 Grundriss der vergleichenden Anatomie der Wirbelthiere. Jena, 1893.
Translation by W. N. Parker, London, 1897.
88. Ziegler, H. E.
1877 Die enstehung des Blutes bei Knochenfischembryonen. Arch. f. mik.
Anat., Bd. 30, 1877.

XII. EXPLANATION OF THE PLATES.

All figures were drawn from actual dissections. Fig. 1 was compiled from
the dissections of three or four specimens, the others from a single specimen.

The arteries are colored red and the veins blue. A vessel drawn in dotted
lines signifies that it passes in or behind a bone, muscle, or organ.

Fic.

II.

EEA OL.
Ophiodon elongatus; Blue cod.

. Represents a general lateral view of the vascular system. The hyoid

vessels are cut and the arch moved caudad from its natural position to
show the deeper branchial vessels, and a considerable part of the caudal

‘portion of the body between the vent and the caudal fin is left out.
. Dorsal view of an injected gill or branchial filament. Meshes of the

capillary network are diagrammatic and are greatly enlarged. Injected
with Hoyer’s chrome yellow gelatin mass. Natural size.

. Dorsal view of a pseudobranchial filament. Efferent vessels in yellow.

Its network is also greatly enlarged. Injected as Fig. 2. Natural size.

. Lateral view of a portion of the efferent pseudobranchial filament

artery. a injected as nig. 2. Leitz 3. (Oc. 1... eyes

. Represents a ventral view of the union of the efferent branchial ar-

teries to form the main arterial trunks, and also the large veinous
trunks emptying into the precaval veins. Only the left dorsal branchial
retractor muscle is indicated. A 15 lb. Ophkiodon, K %.

. A portion of the viscera from the left and dorsal side. Opposite side

of the stomach shown from Fig. 1. 40 lb. Ophkiodon, K 4.

. Origin of the caudal vein from the ventral side, showing its relations

with the lymphatic system. 15 lb. Ophktodon, xX %.

. Deeper dissection of Fig. 7. showing the ending of the caudal artery.
. Anterior view of a caudal vertebra, showing the caudal trunks in sec-

tion. 15 lb. Ophkiodon, XK 4.

. General lateral view of the blood supply to the kidney, testes, and uri-

nary-bladder of a 15 lb. Ophioden, K 4.
Dorsal dissection of the liver to show the main trunks. Portal system
in blue and hepatic system drawn in outline. 201b. Ophkiodon, X \.

(138 )

PLATE |

PROC. WASH. ACAD. SCI., VOL. Vil.

Gow Mes. A ARenv SnA
Neu. Ai. or ALD
My. Nev 1 sie cs
v ERenV. Intev
RCo A Ren. PV

Cou.A

Caw: RCauA Cau V.
LCauA
Hee S
SA, PMes
PMtes A
Hys S.M . Cau.A
Cau.v
‘arm = —hAN
3 = Sa ee
LGo=V LHip A. RCae¥. ars 9 Ae 7 una 10.
LG Int Adl Int Ale ee ee ' SSS
LGash| = Rooe A Inte-A. ~ eS Ur. BY.
: Inti) Int V2) Wa) N (
Danhtl N >. ~\
PsA ‘
— Paint Rania 5
\<<m asia tub. ®P*%sgary
= “ait AGBIA
ea
Int. Ag)
g L.Preev.
UL Oph.A. Oph. V. v pee
pA
cis. EpBrAl) . SubA ee DERM LHep
es Int May
Int Ae

Cae

£8, Am E Be Aw

EBA +
ECer.A EBrAG Gee Mes A

5
i]

pan ay, an A fs4u
x ey Ae ati

Fig. 12

16.

| el Brel) pede

Ophiodon elongatus; Blue cod.

. Represents a general ventral view of the head region, including the
ventral or pelvic fins. Hyoid arch and genio-hyoideus muscle entirely
removed from the left side. Pectorals also not shown. 40 lb. Ophio-
don, X¥%.-

. Eye muscles from the left side. 15 lb. Ophiodon, X }4-

. Shows the blood supply to the inner surface of the right pectoral fin.
40 lb. Ophiodon, X %.

. Represents a doral dissection at the level of the floor of the brain case.

To show the blood supply for the eye, eye muscles, and brain. Floor

of the brain case removed, and the trigeminal-facialis trunks are shown

on the right side. 20 lb. Ophiodon, X 4.

General lateral view in the region of the left head kidney. To show

the blood supply for the posterior part of the brain and the cord.

XH.

(140)

PROC WASH. ACAD. SCi.,

it

D a
——

==
——
—_

I

VOL, Vit

Prec.V.

SubV.(3)

Sub.V. (1) -

SubA. --4-

L.Sub.A.

SubM2)

ESubA fr

3

PROC. WASH, ACAD. SCi,, VOL VII. PLATE iI

Tub ¥)

uy, Suévey

OvMo) Veer’: pcew,

NOMS

CheM. EBcAa)

Vinev.

Vint.
LV Fin V.

V Myo

S RPhacA
Ster hy M.
A L¥finA
Sub¥a} Subse)
i RYFin A
Hypobr. A
Se 12 VP.Ad.M
AbVS. RV inv.
Ayo. i VR.
V.S.AdM.
Ds
= 5.0.M.
ret . i LMOR
‘ DMOR.
Dist ¥
1 Spv.c1 DtarA
SpAu “16
* My
Neuv
AZ Never
q) & New
bs E 2 =
s a
Stank CAA SubA
7
at
FAG
NS
= Pee R in
l DRLMPR
ii
Ny Ni
i \4 fo fave
| /

I5 ore Tr

BGs) 77.

18.

19.

20.

21.

22.

PEATE aL.

Ophiodon elongatus; Bluecod.
flydrolagus collie¢; Chimera (Fig. 26).

Represents the blood supply to and from the nasal sac, as seen from
the right side. Anterior part of the eye shown in outline. 40 lb.
Ophiodon, X 2.

Sameas 17. Nasal sac in outline, to show the veins leaving the inner
side of the sac.

Dissection of the right eye from the inside. The sclerotic coat and
silver layer of the choroid are removed to show the large choroid sinus,
the double rete mirabile or choroid gland, ‘and the iris vein, all of
which run in the vascular layer of the choroid coat. 20 lb. Opkiodon,
natural size.

Same eye, but deeper dissection to show the choroid artery and its rete
mirabile.

Frontal section through the retina and choroid coats, showing the
choroid artery, the choroid sinus, and the retina artery in section.
20 lb. Ophzodon, natural size.

Shows an inside view of the right eye. A sagittal incision was made
nearly through an injected eye and the three coats were folded to the
right. The entire course of the retina artery from its entrance with
the optic nerve until it ends on the lens is distinctly shown. 15 lb.
Ophiodon, X 4.

23. General lateral view of the blood supply to and from the brain. 15 lb.
Ophtodon, natural size.
23a. Blood vessels to and from the auditory organs. 30 lb. Ophiodon,

26.

natural size.

. General dorsal view of the vascular supply of the same brain as Fig.

23. Cranial nerves and anterior encephalic veins shown only on the
right side.

. Same brain as above from the ventral side. Cranial nerves not shown

on the right side.

General lateral view of the main branchial vessels of Hydrolagus
colliez, Chimera. Inserted to show the wide variation in the carotid
antenies.1) <r .

(142 )

PROC. WASH. ACAD. SCI, VOL. VII.

D.ChorV. Cl,

IrV,

|

} OC, WASH. ACAD, SCi., VOL. Vii,

19
D.ChorV. CL
Inv.

I
ih Oph
Opty. Opn

Vas. Cu.B.
Oph. A
ARet.M- Oph
V.RetM

VOhorV.. CB
Inv,

20

23
UR Cor. 23a PLATE II
Bhi cigs city'OOA: RLataX Ala AY - WWI
oirt, °° GGA Cente, OL m o "
ae a ’
- nn DB XD. Shay
Gt Ce ESOC Ee
Alera "7
ry | (Poe AWlNs Aud A Wel /
EncW, [Fecha] Mt : AA HSC
Enea ALerY. fA.
WG W. cea ck’ 24
2 Ms “* CCA Rat ay
SpA
Eh VVIR. ObI.V By
4.CerA
,
al
Chor
ChorS Choris
C Sih
Chor Vaal
Chor A a
er Ret

Opt A EncA Met . MyA P Encv

ACerA PCerA Tub. Sac vas
Ret F. sp AudV
26
AfncA Pines
oe Orl
99 OrbA Dis
a: aig \ Ep Bray
é ‘Orbit
pane RG. {
alP Opts
Ret. F.
Opt.A F.MaxA

4 Ret Chor eSel.

Ret

PLATE IV.

Hexagrammos decagrammus ; Sea trout (Figs. 27 and 28).
Scorpenichthys marmoratus ; Cabezon (Figs. 29 and 30).
Sebastodes auriculatus; Rock cod (Figs. 31 and 34).
Sebastodes flavidus; Rock cod (Figs. 32 and 33).

FIG. 27.

28.

a2.

33°

Represents a general lateral view of the viscera of a 12 in. Hexagram-
mos. ‘The organs are greatly spread out, in order to better display
their blood vessels. & %.

Same specimen as above, showing the opposite or left side of the
stomach.

. General lateral view of the viscera of a 15 in. Scorpenichthys. The

organs are well spread out to show their blood supply and the liver is
not figured. 4.

. Same specimen as above, showing the left or opposite side of the

stomach, and including the liver and the inner surface of the left
pectoral fin. Hepatic system shown in dotted lines.

. Represents a general lateral view of the viscera of a 12 in. Sebastodes

aurtculatus. Body tilted to show the ventral surface of the kidney,
and all the organs spread out so as to best reveal their blood vessels.
Notice the spermatic vein emptying directly into the left precaval vein.
x %.

A portion of the viscera, showing the blood supply for the left side of
the stomach (opposite side from Fig. 31), and the liver of a 10 in-
Sebastodes favidus. This species, though one of the most generalized
of the genus, has a system of blood vessels identical with S. auricula-
tus, which is one of the most specialized. < %.

Shows the blood supply to the gall-bladder and toa gland-like body.
Sebastodes flavidus, X %.

. Shows a variation in the vascular system to the gall-bladder. Sedas.

todes auriculatus, X \%.

(144)

PROC. WASH. ACAD. SCI., VOL. VII.

27

Rien A.

Coe.A.

Coe Mes A, :

nt A,”
RGas.A. /

L.Hep A : _——

BS) Sper V,

Sper.A,
D,Ao : t Ren PV. Ur.BI

“ABIA LSper¥.
ABIV.: LSper A

PROC. WASH ACAD. SCi., VOL. VII

27

29

} CoeMesh | Por
LGashicgen | Ala
@ Lteps

Sper. V
Sper
Ur

Ur. BLA
Ur BLY.

Cor A

LHep.A

RHepk
Int A,

PLATE TW

Proc. Wash. Acad: Sci., June, 1905.

Ae

Fic. 35.

36.

37-
. A portion of the viscera of Azoplofoma from the left and ventral side.

PLATE V.
Anoplopoma fimbria; Black cod.

Represents general lateral view of the principal trunks in the head re-
gion of Anoplopoma, X \4.-

Shows general ventral view of the head region, including the pectoral
and ventral fins of Azoplopoma. Ventral musculature and cesophagus
removed to show the heart and union of the epibranchial arteries to
form the dorsal aorta, cceliaco-mesenteric, and subclavian arteries.
XH.

View of the viscera of Anxoplopoma from the left and dorsal side. %4.

yy.
(146)

PROC. WASH. ACAD. SCI., VOL.

A. BrA. €
f 1 36

: A.BrA.2
H E.BrA2 : V.Ao.' |]

Man. A. --

PLATE V.

PROC. WASH, ACAD. SCI., VOL. VII

C.Porv, Spry

RGasA A Por. Lv view
stip cee eon PY pcey
int ay aah weet aes Sper A. cauy
H int 7
LGasA! Caw, a ERenv
Coe Mesia a tang ae

—— ee tte f
NR A sh

Ex JV iCarA ECarA EBrAz EpBrAy DAo.
NV iEncAiPsA /EBrAs EpBcAe

os ae SubA.CosMes A

Man. A

ced

~

PLATE VI.
fleart of Ophiodon elongatus.

Fic. 39 is from a photograph of the posterior half of a large Ophtodon’s heart,
looking inward and caudad. ‘This heart had previously been injected
with a gelatin mass and hardened in formalin, and the cut was made
directly between the anterior and posterior auriculo-ventricular valves.
x4:

40. As above, is a photograph of the ventral side of a large Ophzodon’s
heart. A portion of the ventral wall of the ventricle had been removed
to the depth of the central cavity to show the semi-lunar and auriculo-
ventricular valves. X 2.

Abbreviations used. — Aur., Auricle. A.V.O., Auriculo-ventricular opening.
A.V.V., Auriculo-ventricular valves. B.Art., Bulbus arteriosus. C.Art., Conus
arteriosus. C.C.V., Central cavity of the ventricle. C.T., Connective tissue.
L.F., Longitudinal folds or ridges. M.L., Muscular layer. S.A.O., Sinu-auric-
ularopening. S.A.V., Sinu-auricular valves. S.V.,Semi-lunar valves. S.Ven.,
Sinus venosus. T.C.A., Trabecule carne auricle. T.C.V., Trabecule carne
ventricle. V.Ao., Ventral aorta. Ven., Ventricle.

Text-fig. 1. — Represents a transverse section through the auricle and ven-
tricle of Ophkiodon elongatus. This section was made through one of the auric-
ulo-ventricular valves. Camera lucida. Leitz No. 2 obj. with lower lens
removed.

Text-fig. 2. — Camera drawing of transverse section through the region of
the conus arteriosus. Same obj. as above.

Abbreviations used. — Aur., Auricle. A.V.Y., Auriculo-ventricular valve.
C.T., Connective tissue. E.M.F., Elastic muscle fibers. End., Endothelium.
L.M., Longitudinal muscle fibers. S.V., Semi-lunar valves. T.M., Transverse
muscle fibers. Ven., Ventricle.

(148)

Proc. WASH. ACAD. Sci., VoL. VII. PLATE VI.

A

BLOOD-VASCULAR SYSTEM OF THE LORICATI 149

XIII. REFERENCE LETTERS AND ABBREVIATIONS USED IN: THE

FIGURES.

The letter D or V prefixed to an abbreviation indicates dorsal or ventral; R
or L, right or left; A or P, anterior or posterior; Ex or In, external or internal.
A series of similar named vessels is numbered from cephalad to caudad.

A.A.
A.Aud.A.
a toe.
A.BI.
A.BI.A.
A.BLYV.
A.Br.A.
Ab. V.S.
A.Cer.A.
A.Cer.V.
Ad.Hym.
Ad.M.M.
Ad.Pal.A.
A.Fil.A.
A.G.BI.A.
A.G.BI.V.
A.Int.A.
PAS inti Ve

A-;Ps.Fil-A.

A.R.
A.Ren.V.
RCE NE:
Aud.A.
Aud.C.
Aud.V.
Aur.
B.Art.
Br. A.
Br.M.A.
Br.O.A.
Br.R.
Ce.
Cx 1) to (5)
Camp.H.
Cau.A.
Cau.V.
(GAGs
(UA OINA

C/.C/.A”.

(GA CEN ANE
(GAGA
CACIN?.
Cen.

Anterior ampulla.

Anterior auditory artery.

Terminal branches or radicals of the left portal.
Air-bladder.

Anterior air-bladder or retia mirabilia artery.
Anterior air-bladder or retia mirabilia vein.

Afferent branchial arteries.

Abductor muscle of ventral spine.

Anterior cerebral artery.

Anterior cerebral vein.

Adductor hyomandibularis.

Adductor mandibulz muscles.

Adductor palatine arch. M. adductor arcus palatini.
Afferent filament arteries.
Anterior gall-bladder artery.
Anterior gall-bladder vein.
Anterior intestinal artery.
Anterior intestinal vein.
Afferent pseudobranchial filament artery.
Anal fin rays.

Afferent or advehent renal veins.
Arterial retia mirabilia of choroid gland.
Auditory artery.

Auditory capsule.

Auditory vein.

Auricle.

Bulbus arteriosus.

Branchial arches.

Dorsal branchial muscle arteries.
Branchiostegal arteries.

Branchiostegal rays.

Pyloric czca.

Five pyloric ceca of Anoplopoma.
Campanula Halleri.

Caudal artery.

Caudal vein.

Cranial cavity arteries.

Common carotid artery.

\ Cranial cavity veins.

Centrum.

150

Cer.
Cer.A.
Cer.H.
Chor.
Chor.A

Chor.A. 1) ?

Chor.A.,2)
Chor.S.
Chor.V.
Cil.B.
@ile
CilNe:
Cave sin:.
Ce.A.

Cce.Mes.A.

Con.Art.
Cor.A.
Cor.V.
GAP aVic
GR:
Cran.
C./V./
C.Ver.
D.Ao.
D.Br.R.M.

D.Chor.V.
Di.Op.M.
D.Lat.A.
IDAzat-Vie

D. & L.M.P.R.

Ds
D.M.A.R.
D.M.D.R.
D.O.M.

ID)-18
IDS).
E.A.
E.Br.A.
Byers

E.Car.A.
E.Fil.A.
Enc.A.
Enc.V.
Epbr.A.
Epi.

E.Ps. Fil.A.

ALLEN

Cerebellum.

Cerebellum artery.

Cerebral lobes or hemispheres.
Choroid coat of the eye.
Choroid arteries.

Superior choroid artery.
Inferior choroid artery.
Choroid sinus.

Choroid veins.

Ramus ciliaris brevis.

Ramus ciliaris longus.

Ciliary nerve.

Caudal lymphatic sinus.
Ceeliac artery.
Ceeliaco-mesenteric artery.
Conus arteriosus.

Coronary artery.

Coronary vein.

Common portal vein. Sedbastodes and Anoplopfoma only.
Caudal fin rays.

Cranial wall.

Connecting vein. Ophiodon and Scorpenichthys only.
Caudal vertebra.

Dorsal aorta.

Dorsal branchial retractor muscle. Retractor arc. branch

dorsalis of Vetter.
Dorsal choroid vein.
Dilator opercular muscle.
Dorsal lateral arteries.
Dorsal lateral veins.
Depressor and levator muscles of the pectoral rays.
Dorsal lymphatic vessel.
Depressor muscle, anal ray.
Depressor muscle, dorsal ray.

Dorsal oblique muscles of the branchial arches (3). Obliqui

dorsales of Vetter.
Dorsal fin rays.
Dorsal spines.
External ampulla.
Efferent branchial arteries.

External branchial levator muscles (4). Levatores arch. branch

externi of Vetter.
External carotid artery.
Efferent filament arteries.
Encephalic artery.
Encephalic vein.
Epibranchial arteries.
Epiphysis.
Efferent pseudobranchial filament arteries.

BLOOD-VASCULAR SYSTEM OF THE LORICATI ESI

E.Ren.A. Efferent renal or revehent renal veins.

E.Sub.A. External subclavian artery.

Eth. Ethmoid.

Ex.J.V- External jugular vein.

Ex.R.A. External rectus artery.

Ex.R.M. External rectus muscle.

Ex.R.V. External rectus vein.

CAN Facial artery.

Fal.P. Falciform process.

Fil. Net. Branchial filament network.

F.Man.A. Facialis-mandibularis artery.

F.Man.V. Facialis-mandibularis vein.

F.Max.A. Facialis-maxillaris artery.

F.Max.V. Facialis-maxillaris vein.

G: Gland.

G.B. Gall-bladder.

Ghs.A. Geniohyoideus artery.

Ghs.M. Geniohyoideus muscle.

Ghs.V. Geniohyoideus vein.

G1.H. Glossohyal.

Veil Hypophysis.

He.A. Hemal arteries.

Race sea Hemal lymphatic vessels.

He.V. Hzemal veins.

Hep.s. Hepatic sinus.

Hep.V. Hepatic vein.

H.Kid. Head kidney.

H.-S. Hemal spine.

H.S.C. Horizontal or external semicircular canal.

Hyo.A. Hyoidean artery.

Hyoid. Hyoid arch.

Hyo.V. Hyoidean vein.

Hyp. Hypural bone.

Hypobr.A. Hypobranchial artery.

Hys.A. Hyohyoideus inferior artery.

Hys.M. Hyohyoideus inferior muscle.

Hys.S.M. Hyohyoideus superior muscle.

Hys.V. Hyohyoideus inferior vein.

IeBre. Internal branchial levator muscles (2). | Levatores arcuum
branchialium interni of Vetter.

I.Car.A. Internal carotid artery.

Telefe Inner iris vein.

ieee Inferior jugular vein.

I.lob.V. » Interlobular veins.

Inf.A. Infundibular artery.

Inf.L. Hypoaria or inferior lobes.

Inf.O.A. Inferior oblique muscle artery.

Inf.O.M. Inferior oblique muscle.

IbabELOMYo Inferior oblique muscle vein.

152

Inf.R.M.
In.H.
Tnsavie
In.Man.M.
Int.
Int.A.q.
Int.A.ia).
Int.A. 1s).
Int.A. a).
Intc.A.
Intc.V.
Int.R.A.
Int.R.M.
Int.R.V.
Int.V.(1)-
Int.V.(1a)-
Int.V.c)-
Int. V.().
Ibe,

Ir-A.

Ge Wc

Tr. V.q).
IL.Sub.A.
L.Sub.A.a.
I.Sub.A.(2).
Tpewey

L.Neu.L.V.

ALLEN

Inferior rectus muscle.

Interhyal.

Internal jugular vein.
Intermandibularis muscle.
Intestine.

Intestinal artery).

Dorsal branch of intestinal artery).
Ventral branch of intestinal artery).
Intestinal artery,2).

Intercostal arteries.

Intercostal veins.

Internal rectus artery.

Internal rectus muscle.

Internal rectus vein.

Intestinal veina).

Dorsal branch of intestinal vein).
Ventral branch of intestinal veina).
Intestinal vein).

Tris.

Iris artery.

Iris vein.

In Anoplopoma.

In Axoplopoma.
In Anoplopoma.

Ventral or minor iris vein.

Internal subclavian artery.

Superficial branch of the\internal subclavian artery.
Profundus branch of the internal subclavian artery.
Jugular lymphatic opening.

Jugular vein.

Kidney.

Liver.

Lateral arteries.

Lateral veins.

Left pyloric ceca artery.

Left pyloric ceca vein.

Left cardinal vein.

Left caudal artery.

Left caudal vein.

Left gastric artery.

Left gastric vein.

Left gastric ramus of the vagus.
Longitudinal hemal lymphatic vessel.
Left hepatic artery.

Posterior or minor left hepatic artery.
Left hepatic vein.

Lingual artery.

Lingual vein.

Lateral lymphatic vessel.

Levator muscles of the anal rays.
Levator muscles of the dorsal rays.
Longitudinal neural lymphatic vessel.

In Anoplopoma.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 153

L.Op.M. Levator opercular muscle.

L.Pal.A. Levator palatine arch. Levator arcus palatini of Vetter.
L.Pal.A.A. Levator of palatine arch artery.

L.P.Gas.A. Left posterior gastric artery.

L.P.Gas.V. Left posterior gastric vein.

WaPorevi- Left portal vein.

[es Speke Left spermatic artery. In Sedastodes.

L.Sper.V. Left spermatic vein. In Sebastodes and Scorpentchthys.
L.Ven.V. Left ventral vein.

L.V.Fin.A. Left ventral fin artery.
Weavekine vis Left ventral fin vein.

Man. Mandible (Dentary, articular, and angular bones).
Man.A. Mandibular artery.

Man.V. Mandibular vein.

Max. Maxilla.

Max.A.(). Anterior or maxillary artery.
Max.A. 2). Posterior maxillary artery.
Max.V. Maxillary vein.

Me.A. Mesencephalic artery.

Mes.A. Mesenteric artery.

Me.V. Mesencephalic vein’

M.Lat.A. Median lateral arteries.

M. Lat.V. Median lateral veins.

My. Myelon, myel, or spinal cord.
My.A. Myelonal artery.

My.V. Myelonal vein.

N.Br.A. Nutrient branchial arteries.
INEBEA Vi Nutrient branchial veins.
Neu.A. Neural arteries.

Neu.L.V. Neural lymphatic vessels.
Neu.V. Neural veins.

N.Fil.A. * Nutrient branchial filament artery.
N.Fil.V. Nutrient branchial filament vein.
N-S. Nasal sac.

INAS 14 Neural spines.

N.S.A. Nasal sac arteries.

N.S. V.q- Anterior nasal sac vein.
N.S.V.(2)- Posterior nasal sac vein.

Obl. Oblongata or medulla oblongata.
ObLYV. Oblongata vein.

Oc:Cl.V. Occipito-clavicularis muscle.
O.D.M. Obliqui dorsales muscles.

Oes. Oesophagus.

Olf.L. Olfactory lobes or bulbs.

O.N.A., Orbito-nasal artery.

O.N.V. Orbito-nasal vein.

Op.A. Opercular artery.

Oph.A. Ophthalmic artery.

Oph.V. Ophthalmic vein.

154

Opt.A.
Opt.L.
Opt.V.
Op.V.
Orb.A.
Ov.
O.V.M.
P.A.
P.A.BI.A.
P.A.BI.V.
Paras.
P.Aud.A.
P.Aud.V.
P2G.E.M.
P.Cer.A.
P.Cer.V.
124 Gal fsa
P.E.Br.A.
Pec.F.
Pel.
Pel.P.
Pence
P.Gas.A.
P.Gas.V.
P.G.BI.A.
Gap lave
Phar.A.
Ph.H.M.
P.Hyo.A.
Pig.L.
P.Mes.A.
P.Mes.V.

P.P.Ad.M.

Prec.V.
Pref.
Prem.
Preo.
Pro.
Ps. A.

P.S.Ad.M.

Pseu.

Ps. Fil.Net.

Py.
Pyl.A.
Ryle
R.Cz.A.
REC Vi.
RAGarovi
R.Cau.A.

ALLEN

Optic or retina artery.

Optic lobes.

Optic or retina vein.

Opercular vein.
Orbital artery.

Ovaries.

In Hydrolagus.

Obliqui ventrales muscles.
Posterior ampulla.
Posterior air-bladder artery.
Posterior air-bladder vein.

Parasphenoid.

Posterior auditory artery.
Posterior auditory vein.
Pharyngo-clavicularis externus muscle.
Posterior cerebral artery.
Posterior cerebral vein.
Pharyngo-clavicularis internus muscle.

Posterior efferent branchial arteries.
Pectoral fin.

Pelvic arch.

Ventral process of the pelvic arch.

Posterior encephalic vein.
Posterior gastric artery.
Posterior gastric vein.

Posterior gall-bladder artery.

Posterior gall-bladder vein.

Pharynx artery.

Pharyngo-hyoideus muscle.
Posterior hyoidean artery.

Pigment layer of the choroid coat.

Posterior mesenteric artery.
Posterior mesenteric vein.

Pectoral profundus adductor muscle.
Precaval vein or Ductus Cuvieri.

Prefrontal.
Premaxilla.

Preopercular.
Prootic process.

Pseudobranchial artery.

Pectoral superficialis adductor muscle.
Pseudobranchia.

In Aydrolagus.

Pseudobranchial filament capillary network.

Pylorus.

Pyloric artery.
Pyloric vein.

Right pyloric ceca artery.
Right pyloric ceca vein.
Right cardinal vein.
Right caudal artery.

Re Cause
Rec.
Rec.A.
Rec. V.
Ren.A.
Ren.P.V.
Ret.
Ret.F.
R.G.

R Gas.A.
R.Gas.V.
R.Hep.A.
R.Hep.V.
R.Hyo.
R.Lat.X.

R.Lat.A.V.
R.Lat.A.X.

R.Man.
R.Man.V.

R.Max.V.

R.P.Gas.A.
R.P.Gas.V.

R.Por.V.
R.Sper.A.
R.Sper.V.
R.Ven.V.

R.V.Fin.A.
R.V.Fin.V.

Sh
Sac.Vas.
Sel:
Scl.A.
Scl.Ir.A.
ScliVi-
S.D.M.
Sil he
SIMIG,,
Sin. Ven.
Si Lobavi.
Sp.A.
Sper.A.
Sper.V.
Spl.
SplA.
Spl.v.
Sp.V.
Sr.A.

BLOOD-VASCULAR SYSTEM OF THE LORICATI 155

Right caudal vein.

Rectum.

Rectus artery.

Rectus vein.

Renal arteries.

Renal portal vein.

Retina.

Retina fissure.

Gland-like body in retina fissure.

Right gastric artery.

Right gastric vein.

Right hepatic artery.

Right hepatic vein.

Ramus hyoideus.

Ramus lateralis vagi.

Facialis portion of the ramus lateralis accessorius.

Vagus portion of the ramus lateralis accessorius.

Ramus mandibularis VII.

Ramus mandibularis trigemini or ramus maxillaris inferior
trigemini.

Ramus maxillaris trigemini or ramus maxillaris superior tri-
gemini.

Right posterior gastric artery.

Right posterior gastric vein.

Right portal vein.

Right spermatic artery. In Sedastodes.

Right spermatic vein. In Sedastodes and Scorpenichthys.

Right ventral vein.

Right ventral fin artery.

Right ventral fin vein.

Suprarenal bodies.

Saccus vasculosus.

Sclerotic coat.

Sclerotic artery.

Sclerotic-iris artery.

Sclerotic vein. ;

Superficial dorsal fin muscles.

Scapula foramen.

Silver layer of choroid coat.

Sinus venosus.

Sublobular veins.

Spinal or myelon arteries.

Spermatic arteries.

Spermatic veins.

Spleen.

Splenic artery.

Splenic vein.

Spinal or myelon veins.

Suprarenal artery.

156 ALLEN

or... Suprarenal vein.

St. Stomach.

Ster.hy.M. Sternohyoideus muscle.

Ster:A. Sternohyoideus arteries.

Ster.V. Sternohyoideus veins.

Sub.A. Subclavian artery.

Sub.s. Subclavian sinus.

Sub. V.q. Internal subclavian vein.

Sub. V.(2). External subclavian vein.

Sub. V.(3). Minor external subclavian vein. In Ofphtodon.
Sup.O.A. Superior oblique muscle artery.

Sup.O.M. Superior oblique muscle.

Sup.O.V. Superior oblique muscle vein.

Sup.R.A. Superior rectus muscle artery.

Sup.R.M. Superior rectus muscle.

Sup.R.V. Superior rectus muscle vein.

aes. Testes.

Thym. Thymus gland.

Thyr. Thyroid gland.

Thyr.A. Thyroid artery.

Trap.M. Trapezius muscle.

Tub. Tuber (cinereum).

AV Transversus ventralis muscle.

Ur. Ureters.

Ur.B1.A. Urinary bladder artery. (Ur.B.A., in Ophzodon.)
Ur.Bl. Urinary bladder.

Ur. BL.) Urinary bladder vein. (Ur.B.V., in Ophcodon.)
Ur.S. Urostyle.

Ut. Utriculus.

V.Ao. - Ventral aorta.

Vas.L. , Wascular layer of the choroid coat.
V.Chor.V. Ventral choroid vein.

Ven. Ventricle.

Ven.A. Ventral artery.

Ven.A.). Posterior ventral artery. In Anoplopoma.
Wena). Ventral or pelvic fins.

Ver. Vertebra.

V.Gas.A. Ventral gastric arteries.

WiaGasavic Ventral gastric veins.

V.Intc.A. Ventral intercostal arteries.

V.Intc.V. Ventral intercostal veins.

V.Lat.A. Ventral lateral arteries.

V.Lat.V. Ventral lateral veins.

Wielaevis Ventral lymphatic vessel.

V.Myo. Ventral myotomes.

Vo. Vomer.

V.P.Ad.M. Ventral or pelvic profundus adductor muscle.” Adductor pro-

fundus pelvis of McMurrich.
V.Ret.M. Venous retia mirabilia of the choroid.

BLOOD-VASCULAR SYSTEM OF THE LORICATI ES

Wisk Ventral spine.

V.S.Ad.M. Ventral or pelvic superficialis adductor muscle. Adductor
superficialis pelvis of McMurrich.

X. Place for injecting the arteries.

Yee Intestinal branch of posterior mesenteric vein.

Gastric branch of posterior mesenteric vein.

il. Olfactory nerve.

Ute Optic nerve.

IT Oculomotor nerve.

IV. Pathetic or trochlear nerve.

V and VII. Trigemino-facial complex.

VI. Abducent nerve.

WAH Auditory nerve.

IX. Glossopharyngeal nerve.

xe Vagus or pneumogastric nerve.

Va): Truncus supra-orbitalis or ramus ophthalmicus superficialis V
and ramus ophthalmicus superficialis VII.

Vo). Truncus infra-orbitalis or buccalis-maxillo-mandibularis.

V3). Truncus hyomandibularis or hyoideo-mandibularis facialis.

V.VIL.R. Trigemino-facialis roots.

V.Scl. Supra-orbital ramus to sclerotic coat.

X.D. Dorsal root of the vagus.

XIV Ventral root of the vagus.

od 2
aye ee
f fe rN
ps Soh oleh |
re OE) ca Te
haha r

me
“Ip.
"t

ced ee

ean