196 



UNDERWATER GUIDE TO MARINE LIFE 



Fig. 99. Gaff-topsail catfish. 



Identification: The two upper jaw barbels are very long, and the lower jaw 

 barbels are only two in number. The fish is named from the shape of the 

 dorsal fin. 



Hahits: The habits of this catfish are similar to those of the former species, 

 but there is a tendency to be more active. The breeding habits are interesting. 

 Very large eggs, up to an inch in diameter, and only about four or five dozen 

 at most in number are laid in June and July. The male carries these eggs in 

 his mouth until they are hatched. After the young hatch out, they are still 

 carried in the male's mouth until the yolk sac is absorbed, at which time they 

 are 3 inches long. During this whole time, a period of two weeks, the male 

 takes no food. 



The "Middle Fishes": Order Mesichthys 



Several quite different suborders are here grouped together because they 

 represent a transition from the herringlike fishes to the advanced spinv-rayed 

 fishes. There is a tendency in these suborders for the ventral fin to be moved 

 forward, the pectorals to be placed high on the body, and the dorsal fin to 

 acquire spines. But, as we shall see, these groups are so different that this order 

 is probably less biologically real, in terms of evolution, than merely con\'enient. 



Pikes: Suborder Haplomi 



Here we meet another predominantly fresh-water group with manv famous 

 members ranging all the way from the powerful pikes and muskellunges to 

 the modest guppies, mollies, swordtails, and platics. There is only one family 

 that reaches salt water, that of the killies. 



KILLIES: Family Cyprinodontidae or Poecilidae 



The round body is compressed behind but depressed at the head so that 

 the mouth is very wide. The ventrals are placed back on the belly and are 

 nearly equal to the pectorals in size. The best field mark is the placement of 

 the dorsal fin far back directly over the rather large anal fin. The many species 

 are usually olivaceous in color and swarm in shallow, salt, brackish, or even 



