OP ARTS AND SCIENCES. 283 



and the tissues below the patches of the chromatophores along the 

 body line are of the same color. The broad flat fin rays, dorsal and 

 ventral, are of a grayish tint ; the eye is blue. In the oldest of the 

 young Lophius which I have had occasion to examine (Plate XVIII. 

 figs. 2, 3) the changes from the preceding stage are very great. 

 Although the body is still laterally compressed, the head, which has 

 greatly increased in size, as well as the body anterior to the anal 

 opening have become somewhat flattened vertically, the first trace of 

 the great flattening so characteristic of the genus. The anterior part 

 of the head projects proportionally far in advance of the orbits, the 

 head sloping less from the base of the anterior dorsal ray than in 

 preceding stages. The pectorals have now become enormous, they 

 extend across the whole width of the body of the young Lophius, 

 they are lobed at the edge, the rays articulated, well marked, and 

 edged with rows of elongated dark pigment spots. The tail fin is well 

 formed, though it still retains its ganoid shape, and the posterior dorsal 

 and anal, though well formed, are still connected by a distinct remnant 

 of the dorsal and ventral embryonic fin fold with the caudal fin. The 

 anterior dorsal now has five rays, with a rudimentary one anterior 

 to the first formed ray. These rays are connected at the base by a 

 fin fold at a much higher point than in younger stages ; they extend 

 far beyond the fold ; the extremities curve down about a quarter of 

 the length of the ray. The increase in length of the ventral rays 

 has been still more remarkable. The original ventral ray is now 

 nearly twice as long as the body of the fish, and the second ray extends 

 fully as far as the extremity of the caudal fin. There are two shorter 

 exterior rays and one interior ray ; they are joined by a membrane 

 extending nearly to the base of the caudal, so that when expanded 

 and seen from above the ventrals appear like regular wings. Their 

 great size and the shape of the peculiar pectorals is well seen in the 

 figure from above (Plate XVIII. fig. 3). The general color of the 

 body of the largest specimens here figured is of a very light, dirty 

 violet tint, of an olive green along the dorsal line ; the body and head 

 are covered by darker violet gray pigment spots. The pigment spots 

 of the ventrals are of an intense black, as well as a few of the spots 

 along the extremity of the urostyle. The pigment cells, of a violet 

 gray, are especially numerous along the line of the pectoral rays, with 

 a row of darker cells at their base (fig. 10). The dorsal, anal, and 

 caudal fins are still very transparent, with a delicate tinge of violet. 

 The young Lophius is very active during its embryonic stages, in 



