Average values for both morphological and optical data have been presented until now, but in the next stage of our study we considered that inter-individual differences of the data might be too large for subsequent calculation or comparison:
e.g., the diameter of the lens itself varied from 430 lm to 525 lm. It would obviously be best if all measurements could be carried out for the same eye, but this
is impossible. As the next best alternative, the paired eyes in individual larvae were examined as follows. One of the paired eyes was first isolated for direct observation of the light path, measurement of the image/object size ratio,
and measurement of the morphological parameters in awholemount preparation. The other eye of the pair was submitted to histological sectioning. Data for 11 pairs of eyes are summarized in Table 3.