. British and Irish Salmonidæ. when the muscles of the tail are of great fts. ^^ ?^, Fis- G. Caudal fm of a sea trout, expanded half aud two-thirds. Locomotion is the main use to which the fins of fishes are put, but even inlocomotion other forces arc frequently or rather generally brought iuto i)lay toassist the fins, whether such is for the purpose of swimming, or for leajiing as inthe salmon while ascending rapidsassistance. The skeleton* or cndo-skolcton of Salmonoids,consists essentially of askull and a vertebral orspinal column (to whichare certain appendages)these forming a protectionto
. British and Irish Salmonidæ. when the muscles of the tail are of great fts. ^^ ?^, Fis- G. Caudal fm of a sea trout, expanded half aud two-thirds. Locomotion is the main use to which the fins of fishes are put, but even inlocomotion other forces arc frequently or rather generally brought iuto i)lay toassist the fins, whether such is for the purpose of swimming, or for leajiing as inthe salmon while ascending rapidsassistance. The skeleton* or cndo-skolcton of Salmonoids,consists essentially of askull and a vertebral orspinal column (to whichare certain appendages)these forming a protectionto the cerebro-spinal ner-vous system and largeblood-vessels present inthe long axis of the vertebra?, of whichthe spinet is made up,consist of a varying num-ber of bones, the bodies ofeach of which are excavated. lis. i^^-- at either end causing themto be bi-concave or amphi-ccelous. The cavity jiro-duced by the apposition ofthe two concave surfaces isfilled up with gelatinoussubstance the remains ofthe notoohord, while it iscovered in by connectingligaments. Consequently,between the vertebras areelastic balls of semifluidconsistence which enablesthem to move freely oneupon another. Fig. 7. Section of two of a salmon, c. cen-trum : lia, arch: :)mal sjune: na, neural arch :jis, neural Bpine. The numerals employed for the various bones in this work are almost identical with thoseof Cuvier and Owen, being as follows:—1, Frontal. 2, Prefontal. 3 (Ef/imoirfc, Cuv.), , Postfrontal. 5 (Basilaiir, Cuv.), Basioccipital. 6 (.S^i/jomlWc pr/Hc-yw^ Cuv.), , Parietal. 8 {Iiiter2>nrictal on Occipital supcricnr, Cuv.), supra-occipital. M (Occipital exteriw,Cuv.), Paroccipital. 10 (Occipital lateral, Cuv.), Exoccipital. 11, Alisphenoid. 12, (li
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Keywords: ., bookcentury1800, bookdecade1880, bookidbritishirish, bookyear1887
