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The bats, Noctilio leporinus and Pizonyx uiuesi, display similar hind foot morphologies specialized for their fish-catching habits. The hydrodynamic drag force of isolated hind feet from fishing and closely related non-fishing bats was measured in a water channel at velocities up to 0.74 ms-l. Drag force increased curvilinearly with increasing water velocity. The highest values of drag force for a given velocity were measured for the fishing bats, which have hind feet 1.8-3.9 times larger than related non-fishing bats. However at high Froude Numbers, the dimensionless drag coefficient (C,) was 23-39% lower for fishing bats compared to non-fishing bats.Cross-sections of the laterally compressed toes of N . leporinus and P. vivesi conformed to hydrofoil designs with minimum drag capabilities, indicated by Fineness Ratio and shoulder position. Moving at high Froude Numbers at the water surface results in the addition of spray drag to the other components of the total drag force ke., frictional, pressure, and wave). Spray drag is suppressed by a foil shape with a long pointed leading edge with a short rounded trailing edge. The configuration of the fishing bat toe with a sharp leading edge and relatively long forebody region compared to the maximum thickness provided a measurable drag reduction at the air-water interface. It was concluded that hydrodynamic drag considerations at the water surface were important in the design of hind feet for fish-catching bats.

Le 4 avril 1988, des pecheurs de Γ Isle-Saint-Georges (Gironde) observerent le matin un dauphin qui remontait la Garonne en accompagnant un bateau de plaisance et, le soir meme, qui descendait la riviere en suivant un petit navire Mammalia, t. 52, n° 4, 1988.

Morphological differences within and between Namibian populations of Elephantulus intufi (N = 116) and E. rupestris (N = 24) were assessed by use of univariate and multivariate analyses. Four external and 16 cranial measurements were recorded for each specimen and assessed for the contribution of age (four classes), sex, and locality. Variation within and between populations of both species is low. Age classes 1 (juveniles) and 2 (subadults) were significantly smaller than the other age classes (3 and 4). There was no evidence of sexual dimorphism in E. intufi. E. rupestris males were significantly larger in six of the 20 measurements and averaged larger in 12 others. Geographic variation was not detected among these specimens. Multivariate analyses provided means to assess the limits of morphological distinction between these two species. Resume. -Les differences morphologiques ä Tinterieur de populations namibiennes d'Elephantulus intufi (N =116) et E. rupestris (N = 24) et entre elles, ont ete etudiees par I'intermediaire d'analyses uni-et multivariees. Quatre mensurations externes et 16 mesures cräniennes ont eto prises en compte pour chaque specimen, et les contributions de Tage (4 classes), du sexe et de la localite a leur variation ont ete evaluees. La variation, qu'elle soit ä l'interieur ou et entre les populations de chaque espece, est faible. Les classes d'age 1 (juveniles) et 2 (subadultes) 6taient composees d'individus significativement plus petits que les autres classes d'age (3 et 4).Nous n'avons pas mis en evidence un dimorphisme sexuel chez E. intufi. Les males d'£. rupestris etaient en revanche significativement plus grands que les femelles pour 6 des 20 mesures, et en moyenne plus grands pour 12 autres. Aucune variation goographique n'a ete detectee parmi ces specimens. Les analyses multivariees ont permis d'evaluer les limites de la distinction morphologique entre ces deux especes.

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