22 PROCEEDINGS OP THE AMERICAN ACADEMY 



Fig. 5. In this stage, considerably larger than the previous one, the change in 

 the outline of the young fish is considerable. The dorsal is highest 

 at its anterior extremity, the caudal is well separated from the 

 dorsal and anal fins, in all the fin-rays are fully formed, the profile 

 of the head is more blunt, and the whole body thickly covered with 

 dark pigment cells. 



„ 6. The differences of this stage from the younger one (fig. 5) consist 

 mainly in the greater width of anterior part of the body ; the dis- 

 tinct pattern of coloration ; the increase in width of the dorsal and 

 anal fins, and their disconnection from the caudal, which has be- 

 come elongated and rounded at the extremity ; the presence of 

 small ventrals ; and the transfer of the right eye forward and up- 

 ward, so that one half is visible above the frontal from the left 

 side. 



„ 7. Is a young Flounder, taken late in the season, but slightly larger than 

 fig. 6, in which, however,, the right eye has passed well over to the 

 left side. The dorsal has extended towards the posterior edge of the 

 right eye, its anterior edge projecting over the eye. The pattern 

 of coloration is similar, in a general way, to that of the adult, and 

 extends into the base of the broad dorsal and anal fins. The ven- 

 trals are larger than in fig. 1. The Flounder in this stage and the 

 preceding stages (figs. 4, 5) habitually rests on the right side, but 

 as yet none of these young fishes show any difference in the color- 

 ation of the right from the left ; the former being still quite as 

 brilliant as the latter in the oldest stage here figured (fig. 6). 



PLATE Vn. 



Rhombus maculatus Mitch. 



Pleuronectes maculatus Storer PI. XXXI. fig. 4. 



Fig. 1. Young specimen, with rudimentary air-bladder, few pigment spots, 

 measuring 5°"" in length. 



„ 2. Somewhat more advanced than fig. 1. The pigment spots greatly de- 

 veloped, but the embryonic dorsal and anal fins show scarcely any 

 advance. 



„ 3. The body has become somewhat broader, the tail far more heterocercal, 

 and rudimentary fin-rays appear both in the dorsal and anal fins. 

 Patches of coloring indicating the future pattern are well defined. 



„ 4. Somewhat more advanced, but slightly longer, than fig. 3. The base of 

 the fin-rays of the dorsal and anal are well developed. The body, 

 with the exception of a bare space of the tail and adjoining part of 

 the body, is of a uniform grayish-brown color, with patches of yel- 

 low, and black longitudinal lines along the upper and lower edges of 

 the notochord, and the base of the dorsal and anal fin-rays, as well 

 as following the muscular bands along the ventral edge. The upper 

 and posterior edge of the stomach is covered by intensely black 

 pigment spots closely crowded together. 



