290 PROCEEDINGS OP THE AMERICAN ACADEMY 



and have observed a couple of stages of the young considerably more 

 advanced than those figured by Mr. Ryder. The youngest of the 

 stages I have observed correspond very closely with the stage figured 

 by Mr. Ryder on Plate IV. fig. 16, Bull. U. S. Fish Com. It was 

 remarkable, however, for having a lateral anal opening close to the 

 notochord, the anal embryonic fin extending unbroken beneath it from 

 the operculum to the extremity of the tail. The older stages are very 

 readily distinguished from other fish embryos by the large pigment 

 spots which are formed one above the other, and by three large patches 

 dividing the posterior part of the body into nearly equal parts, from 

 the extremity of the anal opening to the tail. 



Ctenolabrus cceruleus, Deh 



(Plates XIII. XIV. XV.) 



The egg of Ctenolabrus floats on the surface immediately after being 

 laid, and the eggs in all stages of development are fished up with the 

 hand-net from June to the last part of August. The greater number 

 of the eggs appear to be laid in July. The segmentation of the egg is 

 rapid ; in less than twelve hours after fecundation there are sixteen 

 segmental spheres. In fifty hours the embryonic cap is well formed ; 

 in fifty-two hours the eyes are blocked out ; and the young fish is 

 hatched in from four and a half to five days in the stage of Plate XIII. 

 fig. 1, measuring about 2"™ in length. The yolk bag is large, elliptical, 

 and it (as well as the embryonic fin fold) is free from chromatic cells, 

 which cover only the dorsal part of the body, and stop a little way short 

 of the extremity of the notochord. On the second day after hatching 

 (Plate XIII. fig. 2) the young Ctenolabrus is about 3™" in length, the 

 body is much more elongated, the head especially has lengthened, the 

 distance between the eyes and the otoliths is nearly double, the rudi- 

 mentary pectorals are better marked, and the distance of the vent from 

 the yolk has greatly increased. The black chromatic cells have also 

 increased in number, and are proportionally smaller than in the pre- 

 ceding stages. On the third day after hatching (Plate XIII. fig. 3) 

 the young Fish presents a totally different appearance : the chromato- 

 phores characteristic of the early stages within the egg immediately 

 after hatching have disappeared, there are left but a few large cells 

 in the anterior part of the head, behind the pectorals along the dorsal, 

 while there are in this and the subsequent stage (Plate XIII. fig. 4) 

 large patches of pigment cells, and large chroraatophores at the base 



