CULTURE OF THE SHAD. 161 



" Within eighty-two hours after hatching, great develop- 

 ment has taken place. The tail, though not forked, has 

 taken on its triangular form, and is made up of fine, radiat- 

 ing fibres. The embryonic dorsal and ventral are reduced 

 in breadth, whereby the anal opening is brought close to 

 the body, the base muscles of the true dorsal may also 

 be seen as it begins to form. Along the body the trans- 

 verse muscles show themselves distinctly both above and 

 below the lateral line. The pectoral fins have now their 

 fibres complete, and resemble two little flat brushes. The 

 mouth is pushing forward towards its normal place. It 

 seems to have, in the under lip, a notch, perhaps the 

 point of future union of the maxillaries. The yolk-sac no 

 longer plays an important part, and is reduced to very small 

 dimensions. But the most striking change is the develop- 

 ment of gills, four on a side, and each in its gill-pouch. 

 The gills themselves can be distinguished, like little bows, 

 along which run their veins and arteries. These, together 

 with the size and position of the eyes, give the under sur- 

 face of the head rather the look of that of a skate embryo 

 than of a shad. 



" Such is a hasty sketch of three periods of embryonic 

 life in this Alosa. Of the young, at three months, outlines 

 have already been given.* It should be added, that their 

 jaws are, at this age, armed with fine, sharp, slightly 

 curved teeth, nearly continuous along the upper maxillary 

 and intermaxillary pieces, with a few at the point of the 



* See plate at the commencement of this chapter. 

 L 



