Fakuan— Seventh Report on the Fishes of the Irish Atlantic Slope. 1 31 



portion, which is not overlapped by the scale in front, being armed more or 

 less strongly with superficial spines, characteristic of the species. The 

 remaining portion of the scale consists superficially of a thin covering layer 

 bearing numerous parallel, close-set ridges or striae, which are sometimes 

 continued on to the exposed portion, and then usually merge into the bases 

 of the spines. These striae are parallel to tlie dorsal and ventral margins of 

 the scale and converge anteriorly, meeting in the middle line of the scale at 

 a sharper angle than tlie anterior angle of the scale. The outermost striae 

 thus run out to the anterior margin of tlie scale. It follows that, as the 

 scale grows, new striae are laid down successively along the dorsal and 

 ventral margins of the scale, while the striae which meet the anterior margin 

 of the scale increase by additions to tlieir length. The deeper portion of 

 the scale is, as is nsuaL formed of successive layers, showing a fibrous 

 appearance under the microscope, each layer, when tlie superficial striated 

 layer is scraped off, appearing to have the fibres running in a direction 

 transverse to the preceding one, exactly as in the case of herring scales, as 

 described by Mr. Savage (1919). When examined by polarised light, the 

 method used by Mr. Savage in the case of herring scales, the margin of tiiese 

 layers appear as alternate dark and light hands parallel to the margin of the 

 scale. 



Under a low magnification, by ordinary light, there can often be seen 

 faint concentric markings, or lines, which will be referred to as rinr/s, at 

 various distances parallel to the edge of the scale. 'J'hese seem to be 

 superficial, and to be due to the closing in, bending, or interruption of the 

 striae, which cross them at a low angle, accompanied soinetimes by a faint 

 groove or scar-like marking. They would appear to be liomologous, as far 

 as their outward appearance is considered, to the annual rings on herring 

 scales, wliich are believed to mark the end of a year's growtl:. 'J'he position 

 of these rings, and their relation to the dark and light bands, were investigated 

 in the available species of Macrurids, with the results given below. In 

 tabulating these results, the convention adopted by Dr. Lea and others, when 

 dealing with herring scales, has been followed, the position of the successive . 

 rings being indicated by the proportion which their distance from the centre 

 of the scale bears to the radius of the scale, the latter measurement being 

 expressed by a figure corresponding to the total length of the fish in 

 millimetres, which is shown as the concluding figure of the series. Well- 

 marked rings are indicated by a vertical line ; doubtful rings by a colon. 



The total length of the ilsh, in eases where the tail has been iujured, has 

 been deduced from the length of the head, the proportion of head to length 

 adopted for the purpose being, for Coryphaenoides rupestris, 17'2 : 100 



