290 BRITISH FRESH-WATER FISHES 
the regular inland migration begins. Nearly all the fish caught 
are disposed of locally, in the Forest of Dean, the flesh being 
described as similar, but inferior, to that of the herring. Shad 
occasionally ascend the Tay, the Tweed, and other rivers on the 
east coast, and when one of them gets into the herring-nets it 
is recognised as the “ queen of the herrings.” 
Shad spawn in shallow parts of rivers in May and June, 
descending to the sea again in August. Navigation weirs 
have interfered with its ascent of the Severn, and 
now it is never seen in that river higher than 
Worcester. It is not a sporting fish in any sense, although 
occasionally one may be taken by people “ whiffing”’ for 
mackerel or pollack. In size the shad must be reckoned an 
important fish, most commonly weighing about 3 lb., but often 
attaining double that weight. 
Habits. 
The Twait Shad (Clupea finta) 
FIns. | TEETH. 
As in the Allis shad. As in the Allis shad. 
There are no outward marks of distinction between 
the Twait shad and the Allis shad, save that the former 
is the smaller fish, Inasmuch as both kinds of shad fre- 
quent the same rivers at simultaneous seasons, and observe 
precisely the same habits, it might seem unnecessary to 
differentiate them as separate species; but there is one con- 
stant feature to prove that they are really different fish. In 
the Allis shad, as mentioned above, the outer branchial arch 
supports from sixty to eighty very fine and long gill-rakers 
—horny processes present in most Teleostean fish, which 
serve to protect the delicate organ within from contact with 
such floating substances as might be drawn in. The Twait 
shad, on the other hand, has but twenty-one to twenty-seven 
gill-rakers, which are stout and bony. Its flesh is said to 
