ABBREVIATIONS. 



I. FINS. 



D. Dorsal : the fin or fins along the back. The numerals following the letter 

 in this and other fins indicate the number of fin-rays of various kinds. 

 Numerals separated by a horizontal line signify variation in the 

 number; an oblique line indicates a distinction into two different kinds 

 of rays, the anterior being generally spines or unbranched rays, the 

 posterior branched rays ; a vertical line implies that the numbers on 

 the two sides of it refer to two distinct dorsal fins. The first number 

 or numbers refer to anterior fins or rays. 



Thus D. 7-8 | 1/10-12 means that there are two dorsal fins, the first 

 consisting of 7 or 8 rays all of one kind (probably spines), the second 

 of one ray at the commencement, or anterior end, of the fin of one 

 kind (spine), followed by from 10 to 12 rays of another kind (branched 

 rays). 



A. Anal : the fin (occasionally, but not often, more than one) along the 

 lower border of the body behind the vent. This, like the dorsal, is 

 often composed partly of unbranched rays or spines, partly of branched 

 rays. 



C. Caudal : the fin at the end of the tail. 



The above are known as vertical fins. 



P. Pectoral fins, one on each side, inserted immediately behind the gill-open- 

 ing. They are homologous with the fore limbs in other Vertebrata. 



V. Ventral fins, one on each side, very rarely united, inserted lower on 

 the body than the pectoral fins, and known as abdominal if situated 



