80 THE SCIENTIFIC WORK OF THE 



number of fin-rays^ &c. The genei'al conclusions of the author are : 

 (1) That there is no true racial distinction between the herrings at 

 different parts of the Scottish coasts ; (2) That the only difference 

 in favour of a distinction between the summer and winter herring 

 consists in the more posterior position of the dorsal, pelvic, and 

 anal fins, the doubtfully smaller head, and the slightly lesser size 

 of the summer herring ; but although this holds for the majority of 

 each season, all the extremes of every variation are repeated among 

 the herrings of both seasons. 



In the Report for 1883 Mr. Matthews gives the results of his 

 investigations into the Difference between Herrings and Sprats.* 

 Considerable differences existed among the specimens of each species 

 examined. Various external differences are described, such as the 

 general shape and curve of the body, the position of the operculum 

 and suboperculum, the length of the jaw, &c. These variations 

 are, however, slight and not always easily detected. The best 

 distinctions are the position of the fins and the presence or absence 

 of ventral serration. The scales of the ventral margin have the 

 posterior termination of the median keeled portion sharp and pro- 

 jecting in the sprat, and scarcely developed in the herring. The 

 number of these scales also differs in the young herring and sprat, 

 as does also the number of the scales of the lateral line (fifty-six to 

 fifty-eight in herring and forty-eight in sprat) and the transverse 

 scales (sixteen and eleven or twelve respectively). In the sprat the 

 pelvic fin is anterior to the first ray of the dorsal, but posterior in 

 the young herring. The variations in the position of the other fins 

 is considerable but inconstant ; and the number of rays in the fins 

 varies, except in the pelvic, which has seven in the sprat and nine 

 in the herring. Mr. Matthews states that the distinction based upon 

 the presence of vomerine teeth in the herring and their absence in 

 the sprat is difficult to determine in practice. The chief internal or 

 structural differences are : (1) forty-eight vertebrge in the sprat and 

 fifty-six in the herring ; (2) a less number of gill rakers and branchial 

 filaments in the sprat ; (3) seven or eight pyloric caeca in the sprat, 

 and eighteen to twenty-four in the herring, and they are differently 

 arranged ; (4) in the herring each of the two anterior ducts passing 

 forwards from the swim bladder to the head becomes spindle-shaped 

 and bifurcates, each tubular bifurcation terminating at the ear in a 

 spherical capsule, but in the sprat the spindle-shaped dilatation and 

 subsequent bifurcation are absent. Thus there are four anterior 

 spherical capsules in the herring and only two in the sprat. The 

 most certain distinction, of course, is the presence of ripe milt or roe 

 in the sprat. In winter the reproductive organs in young herrings 

 * Second Report, Append. F, pp. 48—60, pi. iii, 1884. 



