ABBREVIATIONS. 



behind the pectorals, thoracic if below them, jugular if before them in 

 position. The ventrals correspond to the hind limbs of Batrachians, 

 Eeptiles, Birds, and Mammals. 



The ventrals and pectorals are called paired or horizontal fins. 



II. OTHER PAETS OF THE BODY. 



B. Branchiostegal rays (see cut of Perch's head on p. vii). Bony rays sup- 

 porting the membrane within the gill-cover that serves to close the 

 gill-opening. They are attached to the lower portion of the hyoid arch. 



L. 1. Lateral line : a series of perforated scales running along each side in 

 most Teleostean fishes, and generally conspicuous. The numeral re- 

 presents the number of scales in the lateral line ; two numerals with a 

 horizontal line between represent the known extremes of variation: thus 

 L. 1. 50-55 means that the number of scales on the lateral line is 

 known to vary from fifty to fifty-five. 



L. r. The number of transverse rows of scales between the head and caudal 

 fin. When two numerals are given, thus 88/66, the first represents 

 the number of scales above the lateral line, the second that below. 

 When three numbers are given, as 50/48/45, the second figure enume- 

 rates the scales on the lateral line, the first those above, and the third 

 those below. 



L. tr. The number of longitudinal rows of scales between the back and 

 abdomen, usually counted, unless some other part of the side is specified, 

 from the anterior end of the dorsal fin to the ventral. 



Caec. pyl. or C. p. Pyloric caeca or pyloric appendages ; sacs attached to the 

 duodenum. They may be seen, on opening a fish, just beyond the 

 pyloric end of the stomach. 



Vert. Yertebrae. The first numeral signifies abdominal, the second caudal 

 vertebrae. Thus Vert. 10/14 implies 10 abdominal vertebras, 14 caudal. 

 The abdominal vertebras are those between the head and the point of 

 suspension of the anal fin; the majority support ribs, and in none do the 

 parapophyses or processes, one attached low down on each side, unite 

 below to form a haemal spine. The caudal vertebrae have a haemal spine 

 below corresponding to the neural spine above. 



