FISHES OF THE GULF OF MAINE 



529 



visitor to our Gulf from the south; and a second 

 (Masturus lanceolatus) has, perhaps, a claim to 

 mention here, on the strength of one very young 

 suniish that was taken in Massachusetts Bay 

 many years ago (p. 532). 



KEY TO GULF OF MAINE SUNFISHES 



1. There is no evident caudal fin Sunfish, p. 529 



2. There is an evident caudal fin, extending horizontally 



across the posterior edge of the trunk, with a tri- 

 angular lobelike extension a little above the midlevel 

 of the body Sharp-tailed sunfish, p. 531 



Sunfish Mola mola (Linnaeus) 1758 

 Jordan and Evermann, 1896-1900, p. 1753. 



Figure 282. — Sunfish {Mola mola). From 

 Drawing by H. L. Todd. 



Goode. 



Description. — The oblong body of an adult sun- 

 fish (adults alone are seen regularly in the Gulf of 

 Maine) suggests the head and fore trunk of some 

 enormous fish cut off short, for it is truncate im- 

 mediately back of the dorsal and anal fins, and has 

 no caudal peduncle. But it tapers in front of the 



fins toward the snout so that the forward half of 

 the trunk is oval in profile. The fish is less than 

 twice as long as deep, strongly flattened sidewise 

 (about one-fourth as thick as deep), with a very 

 small mouth at the tip of the snout; teeth com- 

 pletely united in each jaw; a very small eye in line 

 with the mouth; remarkably short gill openings, 

 and the nose overhangs the upper jaw as a kind 

 of rough, mobile wart or pad. The soft dorsal fin 

 (there is no spiny dorsal) stands over the anal 

 fin, close behind the midlength of the fish. Both 

 these fins are very much higher than long, tri- 

 angular, with sharply rounded tips, and each has 

 15 to 18 rays, with the seventh ray the longest. 



The fins cannot be laid back, as they can in most 

 bony fishes; and the sunfish propels itself along by 

 waving them from side to side. The caudal fin 

 extends around the whole posterior margin of the 

 body. Confluent with the dorsal and anal fins 

 in the young and hardly separated from them in 

 the adult, it is so short and its rays so hidden by 

 the thick opaque skin that it looks more like a 

 fold of skin than a typical fin. Its general outline 

 is rounded, paralleling the rear outline of the body, 

 but its margin is scalloped, with a rounded bony 

 prominence or knob in line with each caudal ray 

 (11-14) and with a notch between every two of 

 these prominences. We have counted 11 such 

 notches on a fish 3)i feet long, and have record of 

 8 on one of about 4 feet. 17 The pectoral fins are 

 small, rounded, each with 12 or 13 rays, and are 

 situated about halfway up the body close behind 

 the tiny gill openings. There are no ventral fins. 

 The skin is unusually thick (about 1% inches thick 

 in one 47 inches long which we harpooned near La 

 Have Bank on August 7, 1914), very tough and 

 elastic in texture; it is crisscrossed with low ridges, 

 and fins as well as trunk are clothed with small 

 bony tubercles, giving the appearance of shark 

 skin. 



The sunfish is described as glowing luminescent 

 at night in the water. We cannot verify this first 

 hand. But we can bear witness that it grunts or 

 groans when hauled out of the water; that its skin 

 is covered with a thick layer of tough slime, and 

 it is the host of a great variety of parasites, ex- 

 ternal and internal, with copepods and trematodes 

 clinging to its skin and infesting its gills, with its 

 muscles harboring round worms and with various 



" Taken near Boothbay, Maine, and reported to us by Dr. Austin F. Rlggs. 



