THE SKATE. 61 



135. The three or four minute apertures on each side of the dorsal 

 wall of the bladder, by which the ureters open. 



136. The adrenals, inter-renals, dorsal aorta, and cardinal 

 veins, which have the same relations as in the male ( 129- 



In both sexes. 



XXXIII. Carefully dissect away the muscular tissue 

 immediately anterior to the heart and between the 

 two sets of gills, and make out 



137. The synangium or bulbus arteriosus (Figs. 20 

 and 21, b.a\ a white dilatation, connected with the anterior 

 end of the conus arteriosus or pylangium (c.a, 82), and 

 giving off three vessels, one anteriorly, the ventral aorta 

 (y.ad], and one on each side, the posterior innominate 

 arteries (p. in). The ventral aorta passes forwards to the 

 level of the anterior gill cavity, and there divides into two 

 vessels, the anterior innominate arteries (a.in) which 

 are given off at right angles to the ventral, aorta, one on 

 either side. Each anterior innominate artery soon divides 

 into two trunks, each posterior innominate into three ; these 

 five vessels are 



138. The afferent branchial vessels (Figs. 20 and 21, 



the platv 

 mother,}* 



\.remiiy of the plnte, external 

 :-ee 1 66), and gives off branches to 



'. artery (Figs. 20 and 21, hy.br), ru , 





 Lhe bracbi . 



156), and, 

 terior coronary artery ^rigs. - 



aid a posterior 

 . 



