SEA TROUT— SEWIN, ITS DESCRIPTION. 



163 



teeth alternately directed to the right and to the left, and siibseqxiently they 

 drop out, commencing from behind. But the age when this occui-s varies, 

 as will be seen in figure 35, where a sewin 15-1 inches long still possessed four 



along the body of the 

 vomer, while it is by 

 no means infrequent for 

 examples of similar size to 

 retain even more. Occa- 

 sionally two or three 

 remain across the hind 

 margin of the head of the 

 vomer in examples from 

 ten to fifteen inches in 

 length. The teeth in the 

 jaws and palatines are 

 similar to those seen in 

 the salmon-trout. Fins- 



Fig. 35. 

 Teeth on vomer of seuiii 



6-8 inches long : 

 From sewin 15-1 inches long. 



It has been stated that 

 examples of this fish, re- 

 tained some considerable 

 time in a fresh-water pond, 

 had their pectorals more 

 pointed and longer than 

 is usual in their sea- 

 going relatives. The anal 

 fin, similar to that found 

 in the more northern 

 race of sea trout, may 

 have a variation in the 

 number of its rays, which 

 consist of two descrip- 



Fig. 3G. 



1. Anal fin of sewin with 12 rays. 



2. Anal fin of sewin mth 10 rays. 



tions. Anteriorly they are single and undivided, and three or sometimes four 

 in number. The pos- 

 terior rays are divi- 

 ded, the last nearly 

 as low as its base ; 

 of these from seven 

 to nine may bo 

 present: the two 

 shown in fig. 36 

 are from Welsh ex- 

 amples. As regards 

 the form of the cau- 

 dal fin,* figure 37 

 shows outline trac- 

 ings from seven 

 specimens of Truff, 

 White - fish and 

 Welsh sewin, show- 

 ing how exceedingly 

 variable the depth 

 of the cleft may be, at 

 least in fishes up to 

 15 inches in length. 

 Had the extent of the 

 cleft in the northern 

 form been invariably 

 at about what is 

 shown in nos. 4, 6, 

 and 8 in figure 30 

 (see page 156) one 

 would be tempted to 

 believe that a spe- 

 cific difierence might 

 be seen in the 

 amount of excision 

 in this fin. But ex- 

 tending our inquiries 



Fig. 37. 

 Tail fins of female sea trout. 1. Seiein, 6-8 in. long, Tivy. 

 2. Tni/, 8-2 in., Dart. 3. IVIiite-Jish, 12-im.,Teif!,n. 4. Sewin, 

 12-6 in., Towy. 3. Seioin, 13-3 in., Dysiuni. 0. White-fish, 

 13 in., Teign. 7. Sewin, 15-1 in. Towy. 



* Yarrell observed that in old examples the tail became convex and gave a figure of such a 

 fish, which he termed a "Round tail," also a " Sewin " taken from a male specimen 32 inches in 

 length. Giinther asserted that the caudal fin is " forked in specimens 6 inches long ... it shows 

 only a slight emargination in specimens in the grilse stage, and is perfectly truncate in adult 

 examples, but never rounded" (Catal. vi, p. 35). 



11 * 



