DR. J. MURIE ON THE FORM AND STRUCTURE OF THE MANATEE. 1 Wp 
truly astonishing. Besides an axillary, however, I observed another trunk derivative of 
the subclavian, and which may be representative of a thyroid axis, terminating in axillary 
rete. In tracing continuations of the axillary rete I could distinguish circumflex 
anterior and posterior bundles. ‘he brachial rete diminishes as it reaches the elbow 
and passing beneath the pronator radii teres, forms an ulnar rete. This keeps close to 
the bone, under the forearm-muscles, and crosses obliquely to the proximal end of the 
fifth digit. Here, besides muscular radicles, a bunch goes to the palmar aspect of the 
wrist, and by intricate partition helps to constitute the palmar arch. The radial rete 
appears less complicate, but unfortunately its manner of palmar division was not satis- 
factorily made out. 
The multitudinous networks, nuchal, spinal, thoracic, and caudal, are sufficiently like 
those of whales, and have been so frequently referred to by other authors, that I need 
not dwell on them. As regards the intercostal plexuses, these do differ from those of 
Cetacea, inasmuch as, instead of great contorted coils lying superficial to the ribs, each 
intercostal artery dips singly between the ribs, and in the space covered by the pleura 
and muscles divides arborescently. With all due respect therefore to the accuracy 
and acumen of our great leader, Professor Owen, I venture to predict the presence of 
similar rete in the Dugong, where such arterial modification is denied. When unin- 
jected the closely-packed vessels so simulate coarse muscular fibre as readily to deceive 
one unless critically inspected. 
There is an abnormal rete, hitherto unrecorded, in continuance of the internal mam- 
mary. ‘The latter vessel issues beneath the rectus abdominis, opposite the third costal 
interspace, and proceeds upon the transversalis as a rete, which posteriorly anastomoses 
with a returning epigastric series. Anteriorly the rami run outwards in parallel radii 
like the plume of a pen. The abdominal surface of the posterior half of the diaphragm 
is supplied with vessels and nerves arranged in a like fashion. I may advert to a retal 
offshoot of the deep lumbo-caudal mass of vessels, which, for distinction’s sake, may be 
named either sacral, pelvic, or hypogastric rete. Derived from where the costal channels 
strike within the chevron bones, it forms a thin but wide sheet of arterial and venous 
rami, which cover the sacro-coccygeus and parts beneath the urino-genital organs. 
From it vesical and other supplies are given off, the most characteristic being a hypo- 
gastric, obliterated beyond the fundus of the bladder, a uterine, and in the male sper- 
matic plexus, with marked arteria dorsalis penis. 
Circumstances already mentioned prevented my observance of the giving off of the 
abdominal aortic trunks or following the visceral distribution. The mesenteric vessels 
appeared to split into primary, secondary, and tertiary arches without any striking 
peculiarity in the vasia brevia, and the hemorrhoidal arterioles have inosculations with 
the hypogastric rete. 
The veins of the face and head were not followed in detail. Branches, however, were 
observed to return from the submaxillary region and outer side of the jaw; these con- 
2D2 
