1879.] MK-W.OTrL E VONTHEGRODND-BORNB,I.L. 467 



-vould seem to indicate hat t 1 ! ,• ™ " Iread y described, 

 after the arteriea in *£? fi «« ^ = 



Fig. 3. 



Plan of the internal carotid and its branches, with the arteries in the orbit 

 (enlarged). Eight side. ■ 



time in use. The manner in which the obliterated cord ioin, th„ 

 vertebral artery above suggests that the vessel frou nSich Kta£l 

 carotid springs was originally a direct continuation Uf tilf 

 carotid trunk. And tie alteration that W0U U be necessitTdT 

 the obliteration of the main artery would be simok tt ? 



ttet "vf 3 I"? 10 t0 the Vertebral o-al wo Td'Ln WeT/en 



n thTsTo >' "^T^ Sh ° Uld ana ^omose with tL vertebra" 

 m thw position, while the part from 10 to 2 would be the evtlL 

 carotid, giving the usual branches. It seems probabethSfor e 



vest dXed bnM-S 6 f"^^ "* bird the ^trfbuLn ?/ i 

 vessels dittered but little from that usually met with • hut th^ fl, i 



perhaps adds to the difficulty of accounting for the chau^e Sat ha 

 taken place. The theories hitherto propLd to account for S u<^ 

 obliterations of the vessels of the neck in birds have oX dealt with 

 a change affecting one side of the body. This is the onlyt tmce 

 iW...r r < l Uamted ™ th of the symmetrical closure o/two such 

 mportant arteries at a period which, if I am correct in my supuosi 

 tion, was subsequent to their full development and functional activity" 



30* 



