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MANUAL OF ZOOLOGY 



trunk (J>ul. cu. 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. 



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

 laid open, a, a', bristle in left carotid trunk; an. v. v, auriculo-ventricular 

 valves; b,b', 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; I. an, left auricle; Ig. a, lingual artery: / r», longitudinal 

 valve; pul. cu tr, pnlmo-cutaneous trunk; put v, aperture of pulmonary veins; 

 r.au, right auricle; s an. ap, sinu-auricular aperture; spt. aur, 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 



