14 



ARKIV FÖR ZOOLOGI. BAND 7. N:0 25. 



At the point where arteria ventralis takes its origin a minute 

 artery arises, going forwards. I think it corresponds to 

 Allen's arteria thyreoidea (Fig. 9, thyr). Further on the 



Oftk 



KfiU 



Fig. 9. Diagram of the arterial branchial sj^stem of Spheroides testndi- 

 neu8 L. (lateral view), 



la — 3 a, a. branch. afferentes; le — 3 e, a. branch. efferentes ; ce, a. 

 carotis externa ; ci, a. carotis interna ; h, a. hyoidea ; hphr, a. hypobran- 

 chialis ; mand, a. mandibularis ; oph, a. ophthalmica ; ps, psendobranch ; sth. 

 Sk. sternohyoidea ; thyr., a. thyreoidea; ventr, a. ventralis; vji, vena jugula- 

 ris inferior. 



ventral artery gives off another unpaired small artery, supp- 

 lying the sternohyoidean rauscles, which may be called arte- 

 ria sternohyoidea (Fig. 9, sth.), and more caudally the paired 

 arteria hypobranchialis (Fig. 9, hpbr) arises. A vessel that 



