148 
MR. MARSHALL ON THE DEVELOPxMENT 
a small branch descending from one of the veins accompanying the phrenic nerve, 
and so is connected with the left superior intercostal vein. This slender vessel, which 
receives many little branches along its course, is not however part of the metamor- 
phosed left primitive vein, but is formed by the enlargement of the minute inoscu- 
lating veins of the parts which occupy the position of the obliterated vessel. In one 
case indeed, which was carefully dissected, the lower end of this small vein was found 
not to coincide with the trunk of the oblique auricular vein, but to fall into one of 
the lateral tortuous branches of that persistent vessel. 
The arrangement of the valves in the coronary sinus in the adult has been fully de- 
scribed in the introduction to this paper. The abrupt commencement of the sinus, 
pointed out by Dr. J. Reid, is owing to a rounded recess, formed on the auricular 
side of the principal valve (Plate I. fig. \,x), into which the unvalved orifice of the short 
oblique vein (o) is constantly found to open. The sinus itself is described by the 
same observer as having “ the appearance of a muscular reservoir placed at the ter- 
mination of the (coronary) vein, similar to the auricles (auricle?) at the termination 
of the two cavse ; ” but its relations to the left primitive vein in the embryo, and its 
analogies in the lower animals, have not hitherto been mentioned by anatomical 
writers ; though Professor Sharpey has been accustomed to point out, in his lectures, 
the resemblance between the coronary sinus and the lower end of the left superior cava. 
II. COMPARATIVE VIEW OF THE GREAT ANTERIOR VEINS IN MAN AND MAMMALIA. 
Our knowledge of these veins in most of the Mammalia is still deficient, and many 
of the descriptions which exist are incomplete in points of detail. T'o the information 
gathered from other sources, I may add the results of observations made by myself 
on the veins of the Hedgehog, Rabbit, Rat, Mouse and Bat ; of the common Mole, 
the Sheep, Ox, Hog, Guinea Pig and Horse ; and of the Polecat, the Seal, the Dog, 
the Cat and the Monkey*. 
* Since the observations and deductions contained in this paper were completed, and the paper itself entirely 
written, I have seen in the 4th and 5th No. of Mullee’s Archiv for 1848, a short but very interesting com- 
munication by Dr. Baedeleben of Giessen, entitled “ Ueber vena azygos, hemi-azygos und coronaria cordis 
bei Siiugethieren,” in which, after classifying the different Mammalia according to the condition of the Azygos 
and Hemi-azygos veins, as observed by Rathke (op. cit. 1838) and himself, into four groups, — viz. I. those 
having neither of these veins ; II. those having both ; III. those having an azygos only ; and IV. those having 
a hemiazygos only, — he arrives, from a comparison of the adult condition of the veins in the different cases, 
at the same conclusion as myself in regard to the analogy of the coronary sinus with the lower part of the left 
vena azygos or left vena cava superior. “ If,” he says, “ the left canal of Cuviee continues in connection with 
the left jugular vein, so as subsequently to form the left vena cava superior, the coronary vein is said to open 
into the left superior cava. If all the blood is conveyed across the neck by the anastomosing branch between 
the left and the right jugular veins, and the portion of the left jugular between this cross branch and the left 
canal of Cuviee disappears, the last-named vessel continues to be connected with the intercostal system only ; 
and then the coronary vein may be said to end in the left or hemi-azygos, or vice versa. Finally, this connec- 
tion of the left canal of Cuviee being also obliterated, there remains only that portion of the vessel in which 
