120 



and posterior portions which are, respectively, the arteria cerebralis 

 anterior and posterior. From the anterior cerebral artery the optic 

 artery (arteria centralis retinae) arises and, accompanying the nervus 

 opticus, issues into the orbit and enters the eye-ball. The posterior 

 cerebral arteries are connected by cross-commissure and from this 

 commissure a median myelonal artery has its origin. 



The one large branch that has its origin from the lateral dorsal 

 aorta immediately before that artery perforates the parasphenoid is 

 short and stout, and immediately separates into two portions, these 

 two portions being shown, in Maureb's figure of this fish, as inde- 

 pendent branches of the lateral dorsal aorta. One of these two 

 branches, in my specimen, perforates the ascending process of the 

 parasphenoid with the internal carotid, is the "Gefäß zu Nase und 

 Gaumen" of Maurer's descriptions of this fi«h, and the homologue of 

 the orbito-nasal artery of Boulenger's (1904) descriptions of Gadus 

 and of Allen's (1905) descriptions of the Loricati. The other branch 

 is described by Maurer (1884, p. 240) as "der Ast der vom Circiüus 

 cephalicus kommend, die Nebenkieme versorgt", and is the secondary, 

 or definitive afferent pseiidobranchial artery. In my specimen, this 

 latter artery almost immediately separates into two parts one of which 

 plunges into the dorsal portion of the pseudobranch while the other 

 runs downward along the entire length of the edge of that organ, 

 sending branches to it, and beyond the organ continues downward 

 and backward across the internal surface of the hyomandibular. It 

 there sends branches to the tissues of the region, and beyond the hind 

 edge of the hyomandibular extends into the region of distribution 

 of the facialis branch of the external carotid after that branch has 

 traversed the facialis canal through the hyomandibular, but it does 

 not apparently communicate with that artery at any point. As this 

 branch or prolongation of the secondary afferent pseudobranchial 

 artery lies internal (posterior) instead of external (anterior) to the 

 hyomandibular it would seem to indicate that that artery itself is of 

 hyoidean origin and that it cannot accordingly be a persisting portion 

 of any part of the mandibular artery. 



From the pseudobranch the arteria ophthalmica magna arises. 

 Running upward forward and mesially it traverses, with the inter- 

 nal carotid, a foramen through the ascending process of the para- 

 sphenoid, partially separated from the carotid by a projecting spicule 

 of bone, and enters the myodome. There it is connected with its 



