— 53 — 



must He, as they do in Cottus. and as will be later described, in practically the same plane, the internal 

 flange lying wholly dorsal to the external one and the adjoining edges of the two flanges being fused 

 excepting where they enclose a relatively large foramen which perforates the bone so formed. The 

 hyoid artery, in Ophiodon, when it reaches the inner surface of the palato-quadrate, accordingly 

 lies along the inner surface of what is, in reality, the external flange on the hind edge of the meta- 

 pterygoid and not along the inner surface of the body of that bone. There it reeeives the external 

 carotid artery (my nomenclature) which, coniing down along the external surface of the internal 

 flange on the hind edge of the metapterygoid, traverses the foramen between the ventral edge of that 

 flange and the dorsal edge of the external flange. This is also the condition found in Cottus, and 

 Allen's description of Ophiodon is here so particularly referred to simply because it is another of 

 the numerous instances that show that when existing descriptions seem to indicate that important 

 structures, in different animals, differ in their relations to each other, reexaminations and a proper 

 understanding of the parts almost invariably show that such is not the case. There are however 

 instances that do not seem capable of this interpretation. In Triton, for example, Coghill ('06) says 

 that the ramus ophthalmicus profundus V passes dorsal to the ramus superior III, while in Ambly- 

 stoma it passes ventral to that nerve. The supposition that the ophthalmicus V is a superficialis in 

 Triton and a profundus in Amblystoma seems unwarranted, and even this would not explain the 

 conditions found in one specimen of Triton, where Coghill says that the ophthalmicus V passes bet- 

 ween two portions of the r. superior III, lying dorsal to one of them and ventral to the other. 



In Scorpaena, the internal carotid artery, having separated from the external carotid, runs 

 forward and downward in the groove on the outer surface of the proötic, and, traversing the internal 

 carotid foramen enters the myodome across the internal carotid incisure. There it immediately 

 gives off a branch which, on one side of the 45 mm specimen examined, is small, runs forward in the 

 myodome and could there be traced but a short distance. On the other side of this specimen the 

 branch is large, runs forward in the myodome along the internal surface of the ascending process 

 of the parasphenoid, and, at the anterior edge of that process, sends a branch toward the efferent 

 pseudobranchial artery (arteria ophthalmica magna), apparently joining it, and then continues 

 forward as the orbito-nasal artery of Allen's descriptions of Ophiodon. This connection of these two 

 arteries, if it actually exists, which could not be definitely established, would agree with that 

 found by me in Amia. It was not found by Allen in Ophiodon (1. c, p. 55). 



The efferent pseudobranchial artery arises from the opercular hemibranch and, running for- 

 ward external to the cranium, terminates in the choroid gland of the eye-ball. Immediately anterior 

 to the ascending process of the parasphenoid, and immediately anterior also to the point where, on 

 one side of my specimen, the artery apparently reeeives a communicating branch from the internal 

 carotid, it sends a branch downward and mesially, across the ventral edge of the rectus internus 

 and dorsal to the parasphenoid, to join, in the middle line, a corresponding branch from the 

 artery of the opposite side; a transverse commissure between the two arteries thus here being formed. 

 The efferent pseudobranchial artery of Scorpaena thus differs in no respect from that in Ophiodon 

 excepting that, on one side of my specimen, it apparently reeeives a communicating branch from 

 the internal carotid. 



In Pleuronectes, Cole and Johnstone ('Ol, p. 96) say that the two Ophthalmie (efferent pseudo- 

 branchial) arteries ,,perforate the proötics together with the superior jugular veins, passing through 

 the jugular foramina". The external carotids are said to break up along the ventral surface of the 



