698 
PROFESSOR T. J. PARKER ON THE 
I have found no trace of a posterior coronary artery such as exists in the skate 
(11 and 23). 
The nutrient branchial arteries. 
Bronchialarterien, Muller (17). 
The hyoidean hemibranch, as stated above (p. 696), is supplied by several twigs of 
the mandibular artery. The first holobranch, or complete gill, receives its nutrient 
artery (Nu. hr. A. 1) from the longitudinal commissure between the second and third 
efferent branchial arteries. The nutrient artery of the second holobranch (Nu. hr. A. 2) 
arises from the azygos hypobranchial close to its junction with the anterior pair of 
commissures (com. 3) from the efferent branchial arteries ; that of the third complete 
gill (Nu. hr. A. 3) springs from the azygos hypobranchial near its junction with the 
posterior pair of commissures (com. 4). 
The nutrient artery of each holobranch passes along the anterior border of the 
corresponding extra-branchial cartilage. There is a good deal of variation in the 
precise mode of origin of these vessels. 
The pericardial artery 
(Plate 34, fig. 2, Pcard. A.) is given off from the left posterior anastomotic trunk 
(com. 4) between the median hypobranchial and the efferent branchial arteries. It 
passes backwards and at the same time median wards in the dorsal wall of the peri¬ 
cardial cavity, soon dividing into right and left branches. 
5. The cceliaco-mesenteric artery. 
Arteria caliaco-mesenterica (in Torpedo), Hyrtl (11). 
There is an immense amount of variation in the mode of origin and in the distribu¬ 
tion of the splanchnic arteries in Elasmobranchs. In the skate (11, 23) there are large 
coeliac and anterior mesenteric arteries and a small posterior mesenteric, or, more 
correctly, spermatico-mesenteric. In Scymnus (22), the large coeliac artery is supple¬ 
mented by three small mesenteric arteries. In Callorhynchus there are two splanchnic 
•arteries, a coeliaco-mesenteric and a posterior mesenteric, both of considerable size. 
In Mustelus and in Torpedo (11) the main arteries for the alimentary canal and its 
glands are branches of a coeliaco-mesenteric ; in Mustelus there are, however, in 
addition three comparatively small vessels springing separately from the dorsal aorta; 
these I call, from their distribution, the lieno-gastric, and the anterior and posterior 
spermatico-mesenteric. Thus the names given to the more important splanchnic 
arteries of one Elasmobranch are often quite inapplicable to those of another, and I 
have found it impossible in many cases to use Hvrtl’s names, since their employment 
would indicate homologies which do not exist, 
