420 



MANUAL OF ZOOLOGY 



trunk (pal- in- tr). The carotid and systemic trunks com- 

 municate separately with the bulbus, the two pulmo-cuta- 

 neous trunks communicate with the anterior end of the 

 conus by a single aperture placed just below the free end of 

 the longitudinal valve. 



car.cfl 



sysl.t 



CUlr.V.V 



Fig. 252. — Rana temporaria. The heart from the ventral aspect with the cavities 

 laid open, a, a', bristle in left carotid trunk: an. i>. z', atiriculo-ventricular 

 valves: />,/>', bristle in left systemic trunk; c,c', bristle in left pulmo-cutaneous 

 trunk; car. a, carotid artery; car. gl, carotid plexus; c. art, conus arteriosus; 

 car. tr. carotid trunk; /. an. left auricle; lg. a, lingual artery; /. v, longitudinal 

 valve; fill, cu. tr, pulmo-cutanenus trunk; put v. aperture of pulmonary veins; 

 r. an, right auricle; s. an. ap , sinu-auricular aperture; spt. anr, septum auricu- 

 larum; v. v', valves; vt, ventricle. 



After being bound together in the way described for a 

 short distance, the carotid, systemic, and pulmo-cutaneous 

 trunks separate from one another. The carotid trunk divides 



