Animal Life by the Sea-shore. 



insertion of the paired limbs in a position which is the reverse 

 of the primitive. We may distinguish three principal types 

 of ventral fins according to their position : [a] Abdominal, 

 inserted well behind the vertical of the base of the pectorals. 

 (&) Thoracic, below or just behind the base of the pectorals, as in 

 the Wrasse here depicted, (c) Jugular, in front of the base of the 

 pectorals. In some fishes the ventral fins, instead of being paired, 

 are united into one, the whole or part of which maj? be converted 

 into an adhesive disc between and below the pectorals ; fishes 

 so constituted forming a fourth division in this artificial classifica- 

 tion. A fifth division is characterised by the absence of the 

 ventral fins. The unpaired fin on the back is termed the 

 dorsal. In the Wrasse it is single, formed of stiff, spinj' rays 

 in front and of soft branched rays behind ; in other fishes it 

 may be divided into two or three, or the part formed of soft 

 rays may be preceded by a series of isolated spines. The anal 

 fin, opposed to the dorsal, and behind the vent, differs in like 

 manner according to the genera. The fin which terminates the 

 tail, called the caudal fin, may be rounded, truncate, notched 

 or more or less deeplj? forked ; it is sometimes absent. These 

 three fins, the dorsal, the anal and the caudal, ma}' be con- 

 fluent into one, running round the tail. 



Ha\'ing thus explained the terminology of the fins, we may 

 proceed further with the classification chosen as the most 

 appropriate for dealing with the fishes likely to be met with 

 in the surroundiiigs mentioned above ; 



(a) Fishes iinth Abdominal Ventral Fins. — If these fins are 

 formed of several ra3?s, we have probably to do mth the young 

 of marketable fishes, such as the Gre}' i\Iullet [Mugil) or the 

 Priest [Atherina), which are often found among seaweed or in 

 rock-pools, or the Herring, so common in the estuaries at 

 certain seasons. If each of these fins is reduced to a spine, 

 we have the Sticklebacks (Gastrosteiis) . easily recognised by 

 their series of isolated, erectile, dorsal spines. 



(6) Fishes with Thoracic Ventral Fins. — This group includes 

 the Wrasses (Labrus), covered with large imbricate scales, with 

 a single dorsal fin, and thick, fleshy lips concealing strong teeth ; 

 the Bull-heads [Cottas], naked, with large spines on the head 

 and two dorsal fins ; and the Pogge [Agonus), covered with an 

 armour of bony plates and with two dorsal fins. 



(f) Fishes with Jugular Ventral Fins. — ^Vhen these fins 

 are well developed, ^vith five to seven ravs. and two dorsal 

 fins are present, the fish is a Dragonet (CalUonymus) if the 

 ventrals are wide apart from each other and the first dorsal 



