432 THE HERRING FAMILY. 



seawards to spawn, on the south coast, and the eggs are frequent 

 in St Andrews Bay. 



In regard to the rate of growth Cunningham observes that 

 in February, March, April and May little sprats of 2 or 3 inches 

 are about a year old. When 4 to 4^ inches Mr J. Duncan 

 Matthews found them ripe, and this probably in their second 

 year. 



The Allis Shad. {Clupea alosa (pt.), L.) 



This form probably spawns at the same period as its ally, 

 the twaite-shad, viz. from May to July. It ascends rivers for 

 this purpose, and the roe (ovaries) of an example of about 8 lbs., 

 captured in the Tay on the 28th April, 1862, filled the 

 abdomen to a large extent, yet the egg.s were small, and 

 apparently by no means at maturity. They were not in 

 layers or folds as in the salmon, but connected by intermediate 

 tissue. 



The ripe egg resembles that of the other members of the 

 family in having a reticulated yolk, and like the pilchard a 

 large perivitelline space, which, as in the long-rough dab, is 

 developed after its issue from the ovary, and greatly increases 

 the size of the egg — to nearly 4 mm. in diameter, while the yolk 

 is little more than a third of the bulk. The eggs roll in a 

 separate condition on the bottom. 



A complete description of the eggs and larval form of this 

 and the following species would be very desirable. Cunningham 

 in an interesting criticism of the views of Ehrenbaum and of 

 Metzger and Hoek is of opinion that the young examples of the 

 allis shad taken in April, May and June and ranging from 9 to 

 13'6cm. (=3'5 to o'3 in.), are the young of the previous year; 

 while those captured in October and November, and having the 

 length of 7-2 to 14-3 cm. (= 2-3 to 5-4 in.), are those hatched in 

 the preceding spring. 



The eggs of the American shad (Alosa sapidissima), like the 

 foregoing, are slightly heavier than the water, so that they 

 remain in suspension near the bottom. 



