THE HERRING FAMILY l8l 



mm. in length, or from a little less to little more than an inch, 

 and which had advanced further in their transformation. The 

 head, and especially the gill cover and also the abdomen, began 

 to show the silvery coating of the fully developed fish, and the 

 pigment of the back was considerably increased ; but the body 

 was still very slender and narrow, decreasing rapidly from the 

 head backwards. The dorsal fin was still behind the hinder 

 side fin in position. By the middle of July young shad, whose 

 transformation was practically complete, were found to be 

 captured in the stow-nets, having now become thick enough to 

 be retained by its meshes. These were 36 to 46 mm. long, or 

 from i^ to very nearly 2 inches. Their body was almost com- 

 pletely silvered, and the scales developed nearly everywhere, the 

 keeled scales of the belly being well formed. The dorsal fin was 

 now in front of the pelvic, and in some specimens the dark spot 

 on the shoulder was visible. It would appear from this that the 

 transformation of the twait shad is a little more rapid than that 

 of the spring herring in the Schlei ; and that the fish at the com- 

 pletion of the process are on the average somewhat shorter than 

 the herring, although the difference is not great. 



Young shad from the stow-nets were examined and measured 

 by Ehrenbaum at brief intervals from July onwards, and the 

 following records show the rate of growth : 



July 30, 1893 i'8 2-8 inches. 



"August 10, 1892 i"68 2-52 



August 15, 1891.. 2-08 3-12 



August 17, 1893 2-163-24 



September 20, 1893 2'88 4-88 



October 6, 1891 2763-44 



October 15, 1891 3-083-88 



November 15, 1891 3-24-96 



Records of the number and length of young shads captured in 

 the stow-nets at the mouth of the Meuse in Holland have been 

 published in Dutch fishery journals. To summarise these records, 

 with regard to the twait shad, in the month of October eighty- 

 two specimens were taken, the smallest 2'i6 inches long, the 

 largest 6 inches, but the majority 3 to 4 inches. These may be 

 considered the produce of the previous spawning season. In 

 April ninety-three specimens measured 3-56 to 3'68 inches. 

 This shows that some specimens nearly a year old are scarcely 

 bigger than others at five -or six months. In June thirty-one 



