| OCR Text |
Show 1905.] OF THE GENUS RHINOLOPHUS. 107 essential points similar to 1th. affinis. It agrees with the now existing affinis in the pandurate sella and the prolongation of III. . ^ Bat it is considerably higher-developed, chiefly in the following respects: (1) the dentition; (2) the wing-structure; (3) the length of the tail; (4) the beginning, or complete, reduction of the lateral mental grooves; (5) the general size. Ihe peculiar prolongation of the second phalanx of the third finger, described above under Rh. affinis, is preserved in Rh. ferrum-equinum : III.' is more than (or, extremely rarely, at least equal to) 1| the length of III.1. Also IV .2 is lengthened, i.e. more than 12 °f IV.1; it is an interesting fact that, in this particular point, Rh.ferrum-equinum (all races) agrees with Rh. affinis himalayanus, but not with any off the other races of affinis. Besides these two characters, which are simply inherited from an affinis-like ancestor, there is an important modification in another part of the wing, to which we have no parallel in any of the foregoing forms-", viz. a change in the proportionate length of the third, fourth, and fifth metacar pals, as shown in the subjoined table : All the foregoing species Rh.ferrum- equinum (all races; 121 examples) 3rd meta4th meta5th metaForearm. carpal. carpal. carpal. 1000 715 739 710 1000 644 724 743 ) In a ll the forego ing 21 forms o f this third (24 mm., for a supposed length of forearm of 1000 mm.), and the fifth metacarpal is practically of the same length as the fourth t. (2) In ferrum-equinum a considerable shortening of the third metacarpal has taken place ; at the same time a much smaller reduction of the fourth metacarpal has occurred, so as to make the fifth metacarpal, slightly but decidedly, the longest of all. The tail is proportionately longer than in the foregoing species, being, on an average, in the eastern races of ferrum-equinum (nippon, tragatus, regulus) exactly 1 ], in the typical form 1|, the length of the lower leg, whereas proximus, in this point (as well as geographically), is intermediate between the eastern and western races J. In all the foregoing forms, without exception, there are three * But there is an exact parallel in an Ethiopian species, of the affinis type, viz. 1Hi. darlinc/i (see the " General Remarks," below, p. 118). t I t would only have made the table more complicated if I had given separate ciphers for all the foregoing species. The only difference (and an exceedingly small one) is that in simplex, megaphyllus, truncatus, nanus, celebensis, borneensis, virgo, and malayanus the fourth metacarpal is, almost always, a mere trifle longer than the fifth; in nereis, stheno, rouxi, thomasi, and affinis a mere trifle shorter than the fifth. However small this difference is, it is evidently the first faint trace of the modification definitely carried out in ferrum-equinum : the fourth metacarpal al ways shorter than the fifth. J It is hardly necessary to say that a short tail cannot be a primitive character in the order Chiroptera, taken as a whole. But, for some reason or other, we find in the most primitive species of the genus Rhinolophus a very short ta il; in the higher folios of tlie present group we see, again, a lengthening of the tail. |
