internal maxillary 

 ophthalmic artery 



temporal artery 



superior orbita 



external vertebral (above transverse spines) 

 ring around tympanic cavity at level of quadrate 



brachial vessels 



external maxillary 



palatine artery 



internal carotid 



pulmonary artery 



out into throat from base of pulmonary 



A BULLFROG 



external maxillary internal maxillary 



ophthalmic artery 



palatine artery 



mandibular artery 



quadrate 

 hyoid, inner and outer 



pericardium 

 internol carotid and palatine 



external gills 



radix aortae 



brachial artery 

 pulmonary 



B NECTURUS 



Figure 1 1-28. Anterior arteries of Rana and Necturus as seen in semidiogrommatic lateral view. 



mandibular artery. The mandibular artery continues up to 

 the pseudobranch in Lampanyctus or past the pseudobranch, 

 which is supplied by a side branch, in the case of Ophiodon. 

 The mandibular arch of Lampanyctus has afferent and effer- 

 ent parts, while that of Ophiodon is unbroken and enters the 

 dorsal aorta. The efferent pseudobranchial artery in both 

 extends to the eye, where it serves the chorioid coat. In 

 Lampanyctus there is a transverse connective between the 

 vessels of either side which is lacking in Ophiodon. An in- 

 fraorbital artery extends downward and forward from the 

 bilateral dorsal aortae to serve the snout and upper jaw. 



In the case of the actinopterygian fish, it is apparent that 

 parts of the hyoid arch have been done away with or modi- 

 fied. The mandibular arch has been partly retained but 

 modified. The pseudobranch, or mandibular hemibranch, is 

 drained by a special channel running forward to the eye 

 rather than entering the dorsal aorta. 



Chondrichfhyes Although several species of sharks have 

 been described, only a few are well known. Of these, 

 Chlamydoselachus, is similar to the actinopterygian in that the 

 first efferent branchial arch extends ventrally and anteriorly, 

 along with the efferent of the hyoid arch, as a "lateral 

 hypobranchial" or external carotid (Figure 11-30). From 

 this a submental artery extends forward, while an external 

 mandibular extends out and upward to the outer surface of 

 the lower jaw. An afferent mandibular artery parallels the 

 posterior external mandibular; this has cross connections 

 with the anterior efferent hyoidean, and sends branches for- 

 ward on the inner surface of the upper and lower jaws. The 

 external mandibular connects by way of a postorbital stem 

 with the dorsal aorta, while the anterior efferent hyoidean 

 becomes the afferent pseudobranchial. The efferent pseudo- 

 branchial serves the eye and also connects with the dorsal 

 arterial stem, the internal carotid. 



358 



THE CIRCULATORY SYSTEM 



