686 
PROFESSOR T. J. PARKER ON THE 
Raja and Torpedo are described and figured in detail by Hyrtl (11), and there are 
good general accounts of the vascular system in both orders of Plagiostomi in the 
works of Muller (17), Stannius (25), and Milne Edwards (14). By all these 
authors, however, several points of considerable importance are either missed or but 
slightly referred to, while others are more or less inaccurately described. 
In all the more modern text-books of comparative anatomy to which I have had 
access the vascular system of Fishes is very meagrely treated, the manuals of Owen 
(19), Huxley (10), Claus (4), Gegenbaur (7), Bolleston (24), Macalister (13), 
Gunther (8), and Wiedersheim (26), adding little or nothing to the excellent 
though brief account in Stannius’s handbook just referred to. Indeed, the only 
general work I have seen which gives any important information not to be found in 
Stannius is Milne Edwards’s ‘ Legons,’ in which the description of the vascular 
system, and especially of the arteries of Fishes, is full, and, like everything else in 
that invaluable book, admirably clear. 
Great attention has been directed of late years to the Selachians, since it is evident 
that they are the nearest existing representatives of the ancestral stock of the higher 
or gnathostomatous Vertebrata. Their skeleton, muscles, nervous system, urinogenital 
organs, and general embryology have ail been made the subjects of special study 
within the last few years, but, as far as I am aware, the only important contributions 
to our knowledge of their vascular system, since the publication of Milne Edwards’s 
third volume, are Jourdain’s discovery of their renal-portal system (12) and 
Balfour’s researches on the development of their veins (1 and 2). 
I. The Arteries. 
1. The Ventral Aorta and Afferent Branchial Arteries. 
a. Ventral aorta. 
Branchial artery, Monro (16), Owen (19), Gegenbaur (7). 
Arteria hranchialis, Muller (17). 
Artere branchiale, Milne Edwards (14). 
Kiemenarterienstamm, Stannius (25). 
Cardiac aorta, Huxley (10). 
Aorta, aorta ascenders, cardiac aorta, Claus (4). 
Ventral aorta, branchial artery, Balfour (2). 
Hauptstamm der Kiemenarterie, Wiedersheim (26). 
b. Afferent branchial arteries. 
Branches of branchial artery, Monro (16). 
Kiemenarterien, Hyrtl (11). 
Arteres branchiales propres, Milne Edwards (14). 
Branchial arteries, Claus (4). 
