172 MR. F. E. BEDDARD ON THE | Feb. 16, 
The sheath of muscles derived from this vertebral slip in 
Porcula salvania continues on to, or to the neighbourhood of, the 
diaphragm. As already mentioned, I neglected to ascertain. 
whether this sheath and the muscular slip from which it is 
derived were composed of striated fibres. Supposing that they 
are—the most likely supposition, as I think—it may be of interest 
to compare this sheath with that of other mammals. In a con- 
siderable series of papers the late Mr. Gulliver * recorded a striate 
sheath to the esophagus which in man may be regarded merely 
as a slight extension backwards of the striated fibres of the 
pharynx, but which is a more important matter in, for example, 
Rodents and Ungulates. In them the striated layer continues 
back to the hinder end of the esophagus. It is possible that this 
state of affairs is traceable to the attachment of a muscle like that 
described in Porcula, the greater part of which has disappeared 
in other types, leaving only the cesophageal portion. 
(4) Notes upon the Anatomy of the Prongbuck (Antilocapra ameri- 
cana), and on the Colic Helicine in some Artiodactyles. 
In the most recent paper known to me upon the American 
Prongbuck Antelope +, Mr. Lyon enumerates the very abundant 
sources of information respecting the horns of that anomalous 
Antelope, and in discussing the systematic position of Antilocapra 
refers to Dr. Murie’s account of its anatomy in the ‘ Proceedings’ 
of this Society $. I believe that this latter paper contains all that 
is known up to the present time respecting the visceral structures 
of the animal with which I am concerned in the present com- 
munication to the Society. There is thus much less consensus of 
opinion upon the general anatomy of this Bovine than upon the 
nature of the horns, concerning which Mr. Lyon refers to no less 
than 19 separate memoirs or references in larger works. I 
endeavour in the following pages to supplement Dr. Murie’s paper 
by some notes upon certain organs which he has not described or 
not fully described. 
The Azygos veins of Antilocapra are on the plan of those of the 
typical Artiodactyla, meaning in this case, by “ typical,” the 
majority. On the left side is the principal vein. This is formed 
of an azygos which meets a precardinal vein running from before 
backwards to meet the azygos or postcardinal. The former is not 
long. The latter is as usual rather long and extends a moderately: 
long way back towards the diaphragm. The point of junction of 
the two veins and of their connection with the heart is opposite 
to the fifth rib (there are altogether thirteen pairs of ribs). As. 
is the case with other Artiodactyles, as a rule there are also veins 
on the right side belonging to the azygos series, and of these there 
are two which open, the one behind the other, into the precaval 
* P.Z.S. 1869, p. 249, and, P. Z. S. 1870, p..283, with other papers quoted. 
_*+ “Remarks on the Horns and on the Systematic Position of the American 
Antelope,’ P. U.S. Nat. Mus. xxxiv. 1908, p. 393. t P. ZS. 1870, p. 334. 
