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cartilage of tlie palato-quadrate apparatus, while internally it overlaps that cartilage and is in 

 contact with the bind edge of tlie metapterygoid. Its hind edge is in part in contact with the anterior 

 edge of the web of bone that spans the angle between the two Hmbs of the preopercular, and in part 

 is separated from that web of bone by a relatively large opening. This opening is spanned by mem- 

 brane, and the membrane is pierced by the arteria hyoidea and the ramus mandibularis externus 

 facialis, the lateralis fibers of that nerve being accompanied by general cutaneous ones and possibly 

 also by communis fibers, as just above explained. No mandibularis internus foramen, between the 

 symplectic and quadrate, could be fouud. 



The METAPTERYGOID is a subcircular bone slightly concave on its internal surface. It 

 is bounded anteriorly by the entopterygoid, with which it is flexibly connected by tissue; ventrally 

 by the quadrate, from which it is separated by a narrow band of cartilage; and posteriorly by the 

 symplectic and the interspace of cartilage between the latter bone and the hyoraandibular. A small 

 posterior process at the dorsal end of its hind edge is in contact with and bound by tissue to the 

 anterior edge of the ventral end of the hyomandibular, and this process is pierced by a foramen 

 which transmits the external carotid from the outer to the inner surface of the apparatus, the artery 

 there falling into the arteria hyoidea. In the ventral edge of the process there is a notch, which, 

 with the adjoining cartilage, forms a foramen which transmits the arteria hyoidea from the outer 

 to the inner surface of the apparatus. The process on the metapterygoid thus represents, as the hind 

 edge of the bone in Cottus does, the two flanges on the hind edge of the bone of Scorpaena. 



The QUADRATE has a large posterior process, the thick and broad postero-ventral surface 

 of which rests against the dorsal surface of the ventral limb of the preopercular, the point of the 

 process passing into a pocket in that bone. The symplectic groove is simply a broad and shallow 

 depression on the internal surface of the dorsal edge of the bone, immediately anterior to this process. 

 Dorsally the bone is bounded by cartilage which separates it from the metapterygoid, and the anterior 

 edge of the bone forms, with that of the metapterygoid, a continuous line which is slightly convex 

 and lies in a nearly transverse position. The narrow band of cartilage that lies between the two 

 bones is prolonged a short distance beyond tlieir anterior edges, there lies in a depression on the 

 external surface of the entopterygoid, and is exposed on the outer surface of the apparatus between 

 the ecto- and ento-pterygoids. The anterior edge of the quadrate overlaps internally the hind edge 

 of the ectopterygoid, but is itself overlapped internally by a short process at the ventral corner of 

 the latter bone, this latter process being in articular contact with the dorsal surface of the mesial 

 end of the articular head of the quadrate. The quadrate and ectopterygoid thus articulate in a measure 

 with each other, and as their adjoining edges are strongly but flexibly bound together by tissue, and 

 as the anterior edge of the metapterygoid is similarly bound to the hind edge of the entopterygoid, 

 a flexible Joint is here formed in the hyomandibulo-palato-quadrate apparatus. The anterior Pro- 

 longation of the band of cartilage that lies between the quadrate and metapterygoid crosses the 

 Joint uninterruptedly, but being itself flexible does not interfere with the movements of the parts. 

 In the Cyprinidae, according to Sagemehl ('91, p. 582), the palato-quadrate apparatus is also jointed, 

 but in those fishes the Joint is between the palatine and the ecto- and ento-pterygoids and hence 

 not similar to the Joint in Dactylopterus. 



The ECTOPTERYGOID is a stout elongated bone directed antero-dorsally. Its dorso- 

 anterior end suturates with the palatine, the two bones enclosing between them a palatine remnant 



