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Show 1905.] OF THE GENUS RHINOLOPHUS. 93 (compared with the fourth metacarpal); the excessively short tail; and the smaller hind foot. Phylogenetically, Rh. stheno is evidently more closely connected with Rh. nereis than with any other hitherto known Bat. To call the resemblance between these two species (in III.2, IV.', the tail) " convergence," would be a phrase only, not an explanation. There can scarcely be any doubt that the type of Rhinolophus to which the now existing Rh. borneensis belongs, sent off a branch westwards ; a part of this branch, isolated on the Anambas Islands, developed into Rh. nereis; another part, in the Malay Peninsula, into Rh. stheno (cf. the diagram on p. 120). 11. R hinolophus rouxi Temrn. (Plate III. fig. 9 a, b, c, d.) Diagnosis. Allied to Rh. borneensis, but larger, and with considerably longer metacarpals. Third metacarpal 34-38 mm. Forearm 46-51-5 mm. Details. This is a large, continental representative of the borneensis type, characterised chiefly by the much longer metacarpals and the shape of the lancet. In general size, the continental Rh. rouxi bears the same relation to the insular Rh. borneensis as the continental Rh. megaphyllus does to the insular Rh. simplex. The sella is practically parallel-margined from base to summit; not rarely some faint indication of a constriction at the middle can be traced ; summit broadly rounded oft'. In simplex and its closest allies the lancet is long and quite (or almost) cuneate; in borneensis there is some tendency towards a slight emargination of the lateral margins of the lancet; this tendency has been carried almost to an extreme in rouxi: the lancet is hastate, i. e., abruptly narrowed in the middle, the tip well developed and slender (not abnormally shortened, as in thomasi); but still, individually (though, as it seems, rather rarely), in rouxi, the lancet is less abruptly narrowed, as an atavism towards a passed stage. The ears are as in borneensis. Wing-structure almost on the simplex-borneensis stage, i. e., III.2 almost always less than 1| the length of III.1 The rare individual exception, that III.2 is equal to (or a mere trifle more than) 1| the length of III.1, is of some interest as foreshadowing the next important step to be taken in the series of evolution, viz., from rouxi to affinis, in which species III.2 is always considerably more than 1| the length of III.1 Plagiopatagium inserted on, or 1-4 mm. above, the tarsus, i. e., there is evidently some tendency to draw the insertion of this membrane away from the ankle-joint, a little higher up on the tibia; compare with this Rh. affinis. The proportionate length of the tail is as in borneensis. Shull. The skull of Rh. rouxi is larger than that of borneensis, but I fail to find any appreciable difference in the shape-a strono- evidence of the very close relationship between the two species. The individual variation in the size of the skull, in |
