1903-4.] Mr Caiderwood on Bull Trout of Tay and Tweed. 29* 
formulae, number of scales, from adipose fin to lateral line, or in the 
relative proportions of the head, which can he regarded as of any 
specific importance. 
By fishermen these hull trout are judged hy their spotted or 
speckled appearance and by the presence of maggots on the gills. 
In cases where the spots are so few as to render decision doubtful, 
the gills are examined, when, if maggots are present, the fish is 
regarded as a bull trout. For the table, the fish is considered as 
of inferior quality to the salmon, and it does not realise quite as 
high a price in the market. 
I subjoin particulars of eleven of these fish examined at Perth 
on 15th August last, two of the examples being from Loch Ness,, 
the others from the Tay. Length measurements are in each case 
made on the flat, without taking into account the round surface 
of the fish. Scales are counted from posterior margin of adipose 
fin obliquely forwards and downwards to lateral line. 
No. 3. Female. 
Length 42^" x 9" (107 *8 x 23 cm. ) • 
weight 33 lbs. 
Length of head 21 *3 cm. 
Eye to post, of gill cover 12*3 cm. 
Teeth absent from vomer. 
Tail straight ; caudal ped. 8 cm. 
Spots numerous below lat. line and 
on head. 
Scales 12. 
Fin rays, D 14, P 12, A 12, Y 8. 
Maggots on gills. 
A well-marked example. 
No. 4. Female (Tay). 
Length 30|"x6|" (78*5x15*9 cm.) 
weight 11^ lbs. 
Length of head 14 cm. 
Eye to post, of gill cover 8 cm. 
Teeth on head and one on shaft of 
vomer. 
Tail concave ; caudal ped. 5 *2 cm. 
Spots, only two on shoulder, below 
lat. line. 
Scales'll. 
Fin rays, D 14, P 12, V 9. 
Maggots numerous on gills. 
A shapely, salmon-like example. 
No. 1. Female. 
Length 32" x 7^" (81*7 x 18*4 cm.); 
weight 141 lbs. 
Length of head 15 cm. 
Post, margin of gill cover to back of 
eye 8 *5 cm. 
Teeth only on head of vomer. 
Tail straight ; caudal peduncle 5 *8 
cm. 
Spots below lat. line. 
Scales 12. 
Fin rays, D 13, P 13. 
Maggots on gills. 
No. 2. 
Length 39^" x 8^" (101x21*7 cm.); 
weight 26J lbs. 
Length of head 20 cm. 
Eye to post, margin of gill cover 
11 cm. 
Teeth absent from vomer. 
Tail straight ; caudal peduncle 7 *2 
cm. 
Spots, none below lat. line or on 
head. 
Scales 12. 
Fin rays, L> 13, P 13. 
Maggots on gills. 
