44, H. W. MARETT TIMS. 
separate from one another. Radiating from the centrum or 
“ foyer”’ are longitudinal lines, and connecting these trans- 
versely are what he calls the cellular lines. He likens the 
upper surface of the scale to cartilage, the cells of which he 
regards as being the “ corpuscules.” Many of Mandl’s inter- 
pretations will not hold at the present day, but from the point 
of view adopted in the present paper the isolation of the 
individual corpuscles is of considerable interest. In addition 
to this, he came much nearer to a correct interpretation of 
the peripheral growth of the scale than had been done by any 
previous observer. 
In 1873 Baudelot contributed a lengthy paper to the 
‘Archives de Zoologie Experimentale. He examined the 
scales of a great number of fishes, furnishing elaborate 
statistics and instituting comparisons relating to the various 
measurements of scales, the number of concentric markings, 
etc. Beyond this he adds but little to the knowledge of the 
morphology of the scale. His descriptions of the patterns 
upon the upper surface agree in the main with that given 
by Mandl, but using different terminology. Baudelot, how- 
ever, recognised the calcified nature of the upper layer and 
its growth by the deposition of calcareous molecules in the 
membranous zone forming the border of the scale. He 
also gives a short account of the actions of various chemical 
reagents, the results of which I have been able to confirm. 
Following upon this we have the classical works of 
Johannes Miller, O. Hertwig, Peters, Williamson, Hofer, 
Klaatsch, and Nickerson. ‘hese are all too well known to 
need any further reference as to the advances in our know- 
ledge of this subject which each has contributed. 
It must not be supposed that the foregoing pretends to 
afford in any way a complete bibliography, the more im- 
portant of the earlier works alone having been dealt with in 
chronological sequence, in order to furnish a short historical 
sketch of the subject under consideration. 
