. British and Irish Salmonidæ. lungs are invariably situated infra-intestinally or on the ventral side of the intestinal canal. J In August, 1882, Dr. Davy {Plii/siulotiicat Ilesiiinlus) placed a common trout of about aquarter of a pound weight into a good volume of water at 02°, which was pretty rapidly raised TEETH AND INTESTINAL TRACT. 21 The teeth in the salmon,trout, and char are of aconical shape and used morefor capturing than masti-cating their prey : they arepresent in both upper {m)and lower (ma) jaws, on thevomer {v), palatine bones(p), and tongue (t). Theyare frequently slied and a
. British and Irish Salmonidæ. lungs are invariably situated infra-intestinally or on the ventral side of the intestinal canal. J In August, 1882, Dr. Davy {Plii/siulotiicat Ilesiiinlus) placed a common trout of about aquarter of a pound weight into a good volume of water at 02°, which was pretty rapidly raised TEETH AND INTESTINAL TRACT. 21 The teeth in the salmon,trout, and char are of aconical shape and used morefor capturing than masti-cating their prey : they arepresent in both upper {m)and lower (ma) jaws, on thevomer {v), palatine bones(p), and tongue (t). Theyare frequently slied and asconstantly renewed by others Fig. 9. Diagram o£via. mandible appearing from beneath orelse on one side of the dis-carded ones. As age creepson the number of their teethbecome more and morereduced, the teeth-bearingportion of the bones dimin-ish in extent more rapidlyin such forms as frequentthe sea than those which passtheir time in fiesh waters. teeth inside mouth of trout: m. maxilla: : p. palatines: t. tongue: v. The size and arrangement of the vomerine teeth are somewhat varied, as theydiminish more or less rapidly in number with certain conditions, esiJecially thecharacter, whether saline or fresh, of the waters in which the fish live. They also varygreatly in different specimens of even the same universally admitted species, fromwhat exists in the earliest period of their lives when they are in a double row, toold age when all may be absent, consequently it would be unsafe to base specificdifferences upon this dentition. When the tooth-bearing ridge commences tobecome narrower, the teeth are at first forced into a more or less irregular singleline, and subsequently this ridge becomes absorbed commencing from behind andgradually extending forwards and the teeth as a consequence fall out. The teeth in the jaws are comparatively stronger* in fresh-water trout than insalmon or sea trout, as will be subsequently more fully alluded to. The lingual teeth or those ont
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Keywords: ., bookcentury1800, bookdecade1880, bookidbritishirish, bookyear1887
