| Popis: |
Intraspecific variability was investigated in the four external linear measures shown in Figs. 1 and 2 and listed in Table 2. The CVs were averaged in the 35 species in which more than one individual was measured. The largest variabilities, were found to be 3.6 (%) for hemisphere length (HemL) and brain height (BH). In these two measures, it is difficult to arrive at identical values in all individuals of a species. In HemL, the caudal pole is often difficult to fix with the calipers, especially in species where it is low ventrally and projects between the lobulus petrosus (‘flocculus’) and the cerebellar hemispheres, e.g., in Chrysochloris (Figs. 8 and 20). In BH the lowest and highest extremities are not always at the same level (perpendicular to the longitudinal axis of the brain), and thus may be measured at different angles to this axis. The average CV of brain length (BL) is somewhat lower (3.3) than that of HemL and BH. BL may be influenced by the cerebellar uvula, which in different individuals may project to different levels beyond the dorsally adjacent posterior lobe of the cerebellar vermis. The lowest variability in CVs was found for brain width (BW, av. CV = 2.9). BW is easy to measure in all individuals of a species. In Chiroptera, similar differences in CVs have been found in corresponding measures by Stephan and Nelson (1981). |
