. On the anatomy of vertebrates [electronic resource] . the Torpedo carries its electricbatteries. The tympanic pedicles, are short and thick; themaxillary and mandibular arches long and wide, stretching trans-versely across the under part of the head. In the ordinary Sharks the forward prolongation of the cranialcavity gives a quite anterior position, and almost vertical plane,to the fontanelle: three columnar rostral cartilages are produced,two from above, and one from between the nasal cavities, whichprocesses converge and coalesce to form the framework of a kind ofcut-water, at the fore-pa
. On the anatomy of vertebrates [electronic resource] . the Torpedo carries its electricbatteries. The tympanic pedicles, are short and thick; themaxillary and mandibular arches long and wide, stretching trans-versely across the under part of the head. In the ordinary Sharks the forward prolongation of the cranialcavity gives a quite anterior position, and almost vertical plane,to the fontanelle: three columnar rostral cartilages are produced,two from above, and one from between the nasal cavities, whichprocesses converge and coalesce to form the framework of a kind ofcut-water, at the fore-part of the skull. In the place of articular 80 ANATOMY OE VERTEBRATES. condyles, processes extend backward from each side of the occi-pital foramen and clasp, as it were, the bodies of three or fouranterior vertebrae of the trunk. The pterygoidean arches extendoutward, in Carcharias, from the base of the cranium, but, as inembryo osseous fishes, are confluent therewith at both ends. Themaxillary arch, suspended near its closed anterior extremity to 64. Skate (Baia batis) the vomerine part of the base of the skull, is thence extendedbackward to the articulation of the lower jaw. A simple carti-laginous pedicle forms the upper part (pleurapophysis) of themandibular arch, which is completed below by the lower jaw. Afew cartilaginous rays diverge outward and backward from thepedicle, and support a small opercular flap or fin. The hyoid ANATOMY OF VERTEBRATES. 81 arch consists of a basihyoid and two simple ceratohyoid carti-lages ; the stylohyal is ligamentous, as in the Squatina. Shortcartilaginous rays diverge from the ceratohyal to support thebranchiostegal membrane, or hyoid fin. The scapular arch,which we shall find normally articulated with the occiput inosseous fishes, is attached thereto, at a little distance behind thehead, by ligament and muscles in the Sharks, fig. 30, 51 : fromthis arch, also, cartilaginous rays, ib. k, /, immediately diverge forthe support of a radiated
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