1064 



SCANDINAVIAN FISHES. 



li>L;isrs lifivc .siiccL't'ded ill fxplinninj;: the e(]ui\;ilciit 

 |i;irts of tlic i)recefliiig fishes, wiiere tliese arc more 

 iiiid more siiii))lified I))' reduetioii, as well as the cor- 

 r('spoiiding structure of the highei' vertebrates. In some 

 I'.iasmoljranchs (the iJays, tig. 29."!) tiic siidulder-yirdle 



artirnlar condyles (for the pectoral fin), set in an hori- 

 zontal row. Tlie scajinlar jjart lies above the coracoid; 

 but both of tlicni form a contiiuious cartilaginous disi< 

 and are also of a jiiece witli the lower median part of 

 tlie ring. The last-mentioned part has been intei-preted 



forms a closed, flattened ring around the anterior end , by Pakkkk as an equivalent (jf the epicoracoid bone of 



of the abdominal cavity and tlie spinal column behind 

 the last branchial arch, being sus])ended over the con- 

 fluent neural spines of the anterior part of the spinal 

 column. Tlie up]ier jiart of this ring consists of tlie 

 two sim|ilc suprasca]>ular disks;, one on each side of 



the higher vertebrates, where this bone is distinct 

 even in the lowest mammals. In most of the Elasrao- 

 branchs (the Sharks and Chimteras, fig. 294), howevei", 

 the suprascapular cartilages (.ssc) are ])arted from each 

 other and suspended from the membranous investment 



Fiir. 2'J^. Skel,-l,,ii 



1,1 slnmldcT-a 



of (1„. Hays. 



A: Skele-ttjii (if a Skate (Raja )udrosieiisi.s), cf, seen frcni tlic ilc.rsal side. '/,„. Trondhjeiu Fjord, Marcli 17, 1891. Couserviitor SroiiM. 

 fi: ShoiikUT-Kirilli- of a Thoniback (Raja ctavaia), spr-n from Die- ventral side. ' j. .\flor Parker, v. part (.f the 8)iiiial cohnuii : ;//. the 

 first of the three lateral processes fiirTiished with articular siirfaeis for the pectoral tin; ci\ coracoid part; e. ci\ ventral side of the shonMer- 



y'irdle (epicoracoid part). 



the spinal column. The sides thereof are formed by 

 the much moi'e expanded scapular and coracoid parts, 

 ^^dlich are pierced with large foramina (for the passage 



{aponeurosis) of the dorsal muscles only by a prolonga- 

 tion of their own investing membrane (pericJiondriiim), 

 the whole girdle too being more simple and not unlike 



of nerves and blood-vessels) and furnished with three , the pelvic girdle. The cartilage of the latter (figs. 293, 



