PARKER AND DAVIS : HEART BLOOD VESSELS IN FISHES. 171 
to be noticeably smaller than the left. Only the left artery is 
reported present in the following fishes: JPerca fluviatilis (Cuvier et 
Valenciennes, ’28, p. 380, %P1. 7, fig. 1), Salmo (Agassiz et Vogt, ’45, 
p. 125; Hyrtl, ’55, p. 11; Martin, ’94, p. 20), and (according to 
Hyrtl, ’55, p. 11) Lota vulgaris , Lucioperca sa?idra, Silurus giants 
Astro zing el, Labrax lupus , Zeus faber , Xiphius gladius and the 
cyprenoids Aspius, Squalius, Abramis, and Leuciscus. Martin (’94, 
p. 16), however, states that it is the right artery which is present in 
Abramis and the roach (Leuciscus) as well as in the carp. In 
Ceratodus it is also, according to Spencer (’93, p. 8), the right 
artery that is present, the left being entirely unrepresented. It is, 
therefore, probable that in many teleostomes the commissural por¬ 
tion of the coronary system is unilaterally developed and that in 
some cases it is dextral, in others sinistral. 
The Superficial Veins ofi the Heart. 
These veins, often included under the general name of coronary 
veins, are relatively inconspicuous as compared with the coronary 
arteries and have received correspondingly less attention. In Carcha- 
rias littoralis they open into the venous sinus (PI. 3, fig. 7, sn. vn.) 
by two orifices, one to the right and the other to the left of the 
sinu-auricular aperture (apt.). The right orifice leads into the right 
vein fin. cor. dx.), which passes ventrally in the coronary sulcus and 
is finally distributed in the main to the dorsal wall of the bulbus, 
though a few small branches also pass to the right side of the ven¬ 
tricle (Fig. 10, vn. cor. dx.). This corresponds very closely to the 
right or small coronary vein in mammals. The left orifice is the 
opening for three veins, the largest of which (Fig. 7, vn. cor. s.) 
passes to the left and is distributed to the left and ventral aspects of 
the ventricle as well as to the ventral side of the bulbus (Fig. 10, 
vn. cor. s.). This corresponds closely to the left or great coronary 
vein in mammals. The two remaining veins (Fig. 7, vn. crd. m.) 
are small and are restricted to the dorsal surface of the ventricle. 
They correspond collectively to the cardiac veins in mammals. 
In the sharks reported upon by previous investigators the super¬ 
ficial veins always open into the venous sinus near the sinu-auricular 
aperture. In Squalus (de Blainville, ’ll, p. 117) and Scyllium 
(Rose,’ 90, p. 84) there are said to be two such openings, and this is 
