SCIENTIFIC SURVEY. 45 



E. 



Raptatorial — Fitted to seize or snatch any thing. 



Ray — A slender, bony or cartilaginous spine or filament 8uppot^:i^ 

 the membrane of the fins of fishes. 



Ray formula — Each species offish has the same number of rays in 

 their fins and this affords one of the characters to distinguish 

 them. The number of rays is expressed in the following abbre- 

 viated method. Take for instance the common yellow or brindle 

 perch. Its Ray formula would be expressed thus: — B. 7: D. 

 13; 2—13; P. 15; V. 1—15; A. 2— 8; C. 18— which must be 

 read as follows : Branchial rays, seven. Dorsal rays in first fin, 

 thirteen, in second thirteen. Pectoral rays, fifteen. Ventral fins, 

 07)6 spiny ray, fifteen soft ones. Anal fin, two spiny and eight 

 soft. Caudal ray, eighteen. The rays of the common brook trout, 

 which has no spiny rays, would be expressed thus, omitting the 

 branchial ray :— D. 11 : P. 13 ; V. 8 ; A. 11 ; C. 19. 



Roe — The eggs of fishes. In bony fishes these consist of two long 

 bodies resembling the soft roe or milt of male fish, except that 

 they are of a firmer consistency, and are filled with a prodigious 

 number of spheric ovula. They are situated side of the intesti- 

 nal canal, and near the liver and swimming bladder and extend 

 as far as the vent. The ovula (little eggs,) composing these 

 hard roes are so numerous that nearly 350,000 have been counted 

 in a carp eighteen inches long, and in a sturgeon weighing one . 

 hundred and sixty pounds there was discovered nearly 1,500,000. 

 They are enveloped in a delicate membrane which forms a peri- 

 pheral part of the ovary, and joining that of the opposite ovary 

 near its sacral extremity forms with it a common tube that opens 

 behind the vent for the passage of the egg. — Ency. 



s. 



Scales — The small thin plates which cover the bodies of fishes. 



Serrated — Notched like saw-teeth. 



Sound — The air-bag of fishes. 



Spiracula — Small holes through which air is passed. 



Spinigerous — Spine bearing. 



Sub-fusiform — Somewhat spindle-shaped. 



Sub-crescentic — Somewhat crescent or moon-shaped. 



Sub-orbital — Under the eye or orbit. 



Supra ocular — Over the eyes. 



