— 52 — 



course, the artery passes along the inner surface of the external one of the two flanges on the hind 

 edge of the metapterygoid, there lying along the anterior edge of a part of the levator arcus palatini 

 muscle that here has its insertion, and reaches the ventral edge of the internal one of the two flanges 

 on the metapterygoid. There it turns sharply dorso-posteriorly, crosses the internal surface of the 

 hyomandibular and enters the opercular hemibranch at about its dorsal third. At the bend it fuses 

 with the ventral end of the external carotid, that artery forming, in direction, a direct dorsal con- 

 tinuation of that part of the arteria hyoidea that lies below the bend. 



Allen ('05), inhisworkonOphiodon, considers the hyoid artery as ending at the point where the 

 mandibular artery is given off, the artery above that point being called by him the external carotid, 

 with an afferent pseudobranchial brancli arising from it. This manner of naming these arteries is 

 based on the fact that, in Ophiodon, the so-called external carotid is so large, and the hyoid artery 

 so small, that the flow of blood is said to be largely or wholly downward to the point where the man- 

 dibular artery arises, instead of upward from there, toward the hemibranch. In Amia, also, I was 

 led to conclude ('00 c, p. 121) that the flow of blood in the dorsal portion of the arteria hyoidea must 

 be downward, and be derived from the carotid through the pseudobranch. But granting that this 

 be so, the nomenclature seems to me a faulty one, for the artery, up to the hemibranch, is certainly, 

 in its development, the afferent pseudobranchial artery, or arteria hyoidea. Furthermore the course 

 of this so-called part of the externa] carotid artery, as given by Allen in Ophiodon, is not exactly the 

 same as that of the corresponding artery in Scorpaena, the artery being said by Allen (1. c, p. 51) to 

 pass „over the dorsal edge of the hyomandibular", then, ,, along the inner side of the metapterygoid" 

 until it receives the hyoid artery, after which it „comes to the outer surface through a foramen 

 between the symplectic, hyomandibular, preopercular. and quadrate bones". In Scorpaena, this 

 part of the external carotid of Allen's nomenclature passes downward between two flanges on the 

 hind edge of the metapterygoid, then comes to the outer surface of the palato-quadrate through a 

 emall foramen between the metapterygoid and hyomandibular, and, remaining always on the outer 

 surface of the apparatus, receives the hyoid artery which passes outward through an opening between 

 the symplectic, quadrate and preopercular to join it. And in Cottus, Trigla and Dactylopterus 

 strictly similar or equivalent conditions are found, as will be later described. In Scomber, also, this 

 artery has the same course as in these several fishes: for, the connection of the external carotid and 

 hyoid arteries not being given in my work on Scomber, I have had Mr. Henry examine it, in that 

 fish, and he finds the arrangement exactly as above described for Scorpaena, excepting that the 

 two sharp bends found in the hyoid artery (my nomenclature) of Scorpaena do not exist in Scomber; 

 the artery in the latter fish having a nearly straight course as it runs upward from the hyoid arch 

 toward the opercular hemibranch, and the external carotid falling into it at a right angle. This course 

 of the artery in these several fishes seeming to make its course in Ophiodon exceptional, unless there 

 were some error or misconception of its course in Allen's work, I had Mr. Allen reexamine it — for 

 he was at the time attached to my laboratory — and the sketch sent me by him shows that the 

 conditions in Ophiodon are similar to those in Cottus; the hyoid artery (my nomenclature) passing 

 to the outer surface of the palato-quadrate apparatus between the symplectic and preopercular, then 

 crossing the external surface of the hyomandibulo-symplectic cartilage and passing to the inner 

 surface of the apparatus again between the hyomandibular and metapterygoid. Then the artery, 

 to all appearance, runs upward along the inner surface of the hind edge of the metapterygoid 

 as it does in Cottus; but, in Ophiodon, the two flanges on the hind edge of the metapterygoid 



