OF ARTS AND SCIENCES. 'J i ( 



rior part of the body. There is now a double line of dendritic cells 

 extending along the base of the anal and of the dorsal, and a few 

 small cells at the base of the caudal rays. The dorsal and anal fins 

 are separated from the caudal by a deep cut, but the caudal embryonic 

 fin fold is still quite broad, and extends well beyond the base of the 

 tail. 



In the next stage (Plate VI. fig. 4) the young Poronotus has 

 assumed, though faintly, the general coloring of the adult. The whole 

 body is slightly tinted with yellowish brown, the head and anterior 

 part of the body being darkest, with patches of carmine between the 

 eye and base of the brain. The upper part of the head, the anterior 

 part of the dorsal line, and the flanks of the body are well covered 

 with large dendritic chromatophores closely packed together. Large 

 and more distinct cells cover the sides of the body behind the digestive 

 cavity. A row of longitudinal bars of pigment extends along the 

 whole base of the dorsal, while delicate dendritic cells extend along 

 the base of the anal and at the base of the caudal rays. The caudal 

 in this stage has become slightly forked, the dorsal and anal are high, 

 still better separated from the caudal than in the previous stage. The 

 mucous pores of the head are already quite numerous along the oper- 

 culum and near the nostrils. When the young Butterfish has reached 

 a length of 16""" (Plate VI. fig. 5) the body has become much 

 broader, the mucous pores of the head have greatly increased from 

 tlie previous stage figured, the chromatophores of the anterior part of 

 the body, above the head, along the dorsal region, and over the stomach 

 have become very numerous, they extend over the anterior part of 

 the dorsal, with a double line of rectangular spots along the base to 

 the extremity, and a similar double line extends along the base of the 

 ventral. The dorsal and anal, as well as the caudal, have assumed 

 very nearly the outline they have in the adult ; the permanent rays are 

 well articulated in the median fins. 



Atherinichthts notata, Giinth. {Ckirostoma, Gill). 



(Plates X., XI.) 



The youngest specimens of Atherina (Plate X. fig. 1) are striking 

 for their coloring, a light yellow tint extending over the whole em- 

 bryo. The young Atherina is readily recognized from its light-blue 

 eye, with greenish-emerald band above the pupil, and large otoliths, 

 the patches of large chromatophores along the upper and lower side 



