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Show 208 MR. RUDOLF MARTIN ON A FOSSIL [Mar. 3, distance between the antitrochanter and the lateral edge of the area dorsalis is relatively longer in the fossil than in most of the recent medium-sized Ostriches; but on one side this distance cannot exactly be determined in the fossil (because the antitrochanter is broken away and the edge of the area dorsalis is much rounded), and on the other side the individual variation in this regard in S. camelus is very great. The largest individuals of this species differ but little from the fossil, and very probably the fossil pelvis at my disposal must be referred to an adult and rather large animal. The distance between the dorso-mesial borders of the ilia is somewhat shorter in the fossil than in most of the pelves of S. camelus with which I have compared it. But it is in this respect that individual variation has the greatest amplitude, and in the largest pelvis of S. camelus at my disposal this distance is equal to that of the fossil. S. karatheodoris. S. camelus. Costal process of the 1st " true sacral vertebra " to the distal border of the 2nd postsacral vertebra............................ Width of the centra of the " true sacral 7*8 cm. 9'2 cm. vertebrae " ................................................. 2*5 1-8 Width of the centrum of the 2nd postsacral vertebra ..................................................... 2-8 2-3 Greatest width of the dorsal surface of the pelvis ......................................................... 12 12-2 Plummet in the dorsal border of the antitrochanter to the median plane ........... ca, 12 12 Plummet in the dorsal border of the anti-trochanter to the plane of the dorsal surface of the pelvis ................................ ca.6'5 4 The results show that there are great differences in the proportions of the pelvis of the two species which justify a separation of the fossil from the recent Ostrich. The individual variation, however, does not allow us to place the two forms in different genera, because it greatly reduces the differences above mentioned. I have said that the separation of the two Ostriches in different species was justified. On the other hand, the question arises, whether or no the differences between the two forms be not the consequences of a pressure acting during the great tectonic transformations in the region between Asia Minor and Greece. A study of the other fossils of Samos, however, gives no evidence of such a force ; there is only a lateral compression to be seen, a result of the pressure of the weight of the more recent strata. These considerations add to the importance of the features which I have selected for special comment, whilst on the other hand other |